diff --git a/coin change.py b/coin change.py
new file mode 100644
index 0000000..73c38e3
--- /dev/null
+++ b/coin change.py	
@@ -0,0 +1,14 @@
+# PROGRAM TO FIND   MINIMUM  NUMBER  OF  COINS  NEEDED  TO  MAKE   A  CERTAIN  AMOUNT................
+
+def coinChange(centsNeeded,coinValues):
+    minCoins=[[0 for j in range(centsNeeded+1)] for i in range(len(coinValues))]
+    minCoins[0]=range(centsNeeded+1)
+    for i in range(1,len(coinValues)):
+        for j in range(0,centsNeeded+1):
+            if j<coinValues[i]:
+                minCoins[i][j]=minCoins[i-1][j]
+            else:
+                minCoins[i][j]=min(  minCoins[i-1][j] , 1 + minCoins[i][j-coinValues[i]] )
+    return minCoins[-1][-1]
+print coinChange(8,[1,2,5,10,20,50,100,200])    # 1 should always be in the if not then append 1 else will be wrong 
+
diff --git a/coin sums.py b/coin sums.py
new file mode 100644
index 0000000..06e727e
--- /dev/null
+++ b/coin sums.py	
@@ -0,0 +1,16 @@
+l=[1,2,5,10,20,50,100,200]
+t=input()
+while t:
+    t-=1
+    n=input()
+    w=[]
+    for i in range(n+1):
+        if i==0:
+            w.append(1)
+        else:
+            w.append(0)
+    for i in range(len(l)):
+        x=l[i]
+        for j in range(x,n+1):
+            w[j]+=w[j-x]
+    print w[n]
diff --git a/detect_html_tags.py b/detect_html_tags.py
new file mode 100644
index 0000000..ad8c675
--- /dev/null
+++ b/detect_html_tags.py
@@ -0,0 +1,18 @@
+from HTMLParser import HTMLParser
+
+
+class MyHTMLParser(HTMLParser):
+    def handle_starttag(self, tag, attrs):
+        print tag
+        for attr in attrs:
+            print "->"," > ".join(attr)
+
+parser = MyHTMLParser()
+
+html = ""
+for i in range(int(raw_input())):
+    html += raw_input()
+    html += '\n'
+
+
+parser.feed(html)
diff --git a/factorial.py b/factorial.py
new file mode 100644
index 0000000..5c6748a
--- /dev/null
+++ b/factorial.py
@@ -0,0 +1,27 @@
+t=input()
+while t>0:
+    t-=1
+    le=0
+    fact=[0]*(100001)
+    fact[0]=1
+    m=input()
+    for k in range(2,m+1):
+        r=0
+        arr=[0]*(100001)
+        for i in range(le+1):
+            arr[i]=fact[i]
+        for i in range(le+1):
+            fact[i]=(arr[i]*k+r)%10
+            r=(arr[i]*k+r)/10
+        i+=1
+        if r!=0:
+            while r!=0:
+                fact[i]=r%10
+                r/=10
+                i+=1
+        le=i-1
+    x=((fact[:le+1])[::-1])
+    for i in range(len(x)):
+        x[i]=str(x[i])
+    print ''.join(x)
+    
diff --git a/gcd_n_nos.py b/gcd_n_nos.py
new file mode 100644
index 0000000..43857ed
--- /dev/null
+++ b/gcd_n_nos.py
@@ -0,0 +1,17 @@
+def gcd(x,y):
+    while(y!=0):
+        temp=x%y
+        x=y
+        y=temp
+    return x
+def gcd_n(l):
+    if(len(l)>=2):
+        x=gcd(l[0],l[1])
+        for i in range(2,len(l)):
+            x=gcd(x,l[i])
+        return x
+    else:
+        return l[0]
+'''l=list(map(int,raw_input().split()))
+print gcd_n(l)
+'''
diff --git a/knapsack.py b/knapsack.py
new file mode 100644
index 0000000..a6d8714
--- /dev/null
+++ b/knapsack.py
@@ -0,0 +1,17 @@
+def knapsack(W,wt,val,n):
+    k=[]
+    for i in range(n+1):
+        k.append([0]*(W+1))
+    for i in range(n+1):
+        for w in range(W+1):
+            if i==0 or w==0:
+                k[i][w]=0
+            elif wt[i-1]<=w:
+                k[i][w]=max(k[i-1][w],val[i-1]+k[i-1][w-wt[i-1]])
+            else:
+                k[i][w]=k[i-1][w]
+    return k[n][W]
+val=[60,100,120]
+wt=[10,20,30]
+W=50
+print knapsack(W,wt,val,len(val))
diff --git a/lcs.py b/lcs.py
new file mode 100644
index 0000000..3ba110f
--- /dev/null
+++ b/lcs.py
@@ -0,0 +1,25 @@
+def lcsd(x,y):
+    m=len(x)
+    n=len(y)
+    global c
+    c=[]
+    for j in range(n+1):
+        c.append([0]*(m+1))
+    for i in range(1,m+1):
+        for j in range(1,n+1):
+            if x[i-1]==y[j-1] :
+                c[j][i]=str(c[j-1][i-1])+str(x[i-1])
+                
+            else:
+                c[j][i]=max(str(c[j-1][i]),str(c[j][i-1]))
+                
+    return c[n][m]
+    
+
+
+
+a=raw_input()
+b=raw_input()
+m=lcsd(a,b)
+ff=m.replace('0','')
+print ff,len(ff)
diff --git a/lcs_n_numbers.py b/lcs_n_numbers.py
new file mode 100644
index 0000000..38f25df
--- /dev/null
+++ b/lcs_n_numbers.py
@@ -0,0 +1,28 @@
+def lcsd(x,y):
+    m=len(x)
+    n=len(y)
+    global c
+    c=[]
+    for j in range(n+1):
+        c.append([['@']]*(m+1))
+    for i in range(1,m+1):
+        
+        for j in range(1,n+1):
+            if x[i-1]==y[j-1] :
+                c[j][i]=list(c[j-1][i-1])
+                c[j][i].append((x[i-1]))
+      
+            else:
+                if len(c[j-1][i])>=len(c[j][i-1]):
+                    c[j][i]=list(c[j-1][i])
+                else:
+                    c[j][i]=list(c[j][i-1])           
+    return c[n][m]
+    
+a=list(map(int,raw_input().split()))
+b=list(map(int,raw_input().split()))
+m=lcsd(a,b)
+for i in m:
+    if(i!='@'):
+        print i,
+
diff --git a/ncrmodm.py b/ncrmodm.py
new file mode 100644
index 0000000..b6b881e
--- /dev/null
+++ b/ncrmodm.py
@@ -0,0 +1,11 @@
+def modinv(a,m):
+    return pow(a,m-2,m)
+def nCrmodm(n,k,m):
+    num=1
+    for i in range(k):
+        num=(num*(n-i))%m
+    den=1
+    for i in range(1,k+1):
+        den=(den*i)%m
+    return (num*modinv(den,m))%m
+print nCrmodm(5,2,pow(10,9)+7)
diff --git a/pow(a,-b,x).py b/pow(a,-b,x).py
new file mode 100644
index 0000000..5153019
--- /dev/null
+++ b/pow(a,-b,x).py
@@ -0,0 +1,26 @@
+L = 10**6
+# sieve of Eratosthenes
+primes = []
+is_prime = [False]*2 + [True]*(L-1)
+for p in xrange(2,L+1):
+    if is_prime[p]:
+        primes.append(p)
+        for n in xrange(2*p,L+1,p):
+            is_prime[n] = False
+# calculate Euler's totient function
+phi = [0]*(L+1)
+for n in xrange(1,L+1):
+    phi[n] = n
+for p in primes:
+    for n in xrange(p,L+1,p):
+        phi[n] -= phi[n]/p
+t=input()
+while t>0:
+    t-=1
+    a,b,x=map(int,raw_input().split())
+    if b<0:
+        ans=pow(a,phi[x]-1,x)
+        print pow(ans,-b,x)
+    else:
+        print pow(a,b,x)
+
diff --git a/prime summations.py b/prime summations.py
new file mode 100644
index 0000000..e6c7de2
--- /dev/null
+++ b/prime summations.py	
@@ -0,0 +1,16 @@
+def primes_sieve(n):
+    sieve=[True]*n
+    for i in xrange(3,int(n**0.5)+1,2):
+        if sieve[i]:
+            sieve[i*i::2*i]=[False]*((n-i*i-1)/(2*i)+1)
+    return [2] + [i for i in xrange(3,n,2) if sieve[i]]
+t=input()
+for ii in range(t):
+    n=input()   
+    primes=primes_sieve(n+1)
+    ways=[0 for i in range(n+1)]
+    ways[0]=1
+    for i in range(len(primes)):
+        for j in range(primes[i],n+1):
+            ways[j]+=ways[j-primes[i]]
+    print ways[n]
diff --git a/prime.py b/prime.py
new file mode 100644
index 0000000..1f52e66
--- /dev/null
+++ b/prime.py
@@ -0,0 +1,24 @@
+def main(m, n):
+    primes = [False for x in xrange(n-m+1)]
+    p = 2
+    while p*p <= n:
+        r = m / p
+        r *= p
+        for j in xrange(r, n+1, p):
+            if j != p and j >= m:
+                primes[j-m] = True
+        p += 1
+ 
+    for i in xrange(n-m+1):
+        if not primes[i] and m+i != 1:
+            print m + i
+ 
+ 
+if __name__ == "__main__":
+    t = int(raw_input()) ## nb of test cases
+ 
+    for k in xrange(t):
+        m, n = map(int, raw_input().split())
+        main(m, n)
+        if k < t-1:
+            print "" 
diff --git a/prime_best.py b/prime_best.py
new file mode 100644
index 0000000..c2cdeea
--- /dev/null
+++ b/prime_best.py
@@ -0,0 +1,50 @@
+
+#fastest and calculates prime number below  n 
+def primes_sieve_best(n):
+    sieve=[True]*n
+    for i in xrange(3,int(n**0.5)+1,2):
+        if sieve[i]:
+            sieve[i*i::2*i]=[False]*((n-i*i-1)/(2*i)+1)
+    return [2] + [i for i in xrange(3,n,2) if sieve[i]]
+def prime_biggy(n):
+    biggy=[1]*(n+1)
+    for i in xrange(2,int(n**0.5) + 1):
+        if biggy[i]==1:
+            j=2
+            while j*i<=n:
+                if biggy[j*i]==1:
+                    biggy[j*i]=0
+                j+=1
+    biggy2=[]
+    for i in range(2,n+1):
+        if biggy[i]==1:
+            biggy2.append(i) 
+    return biggy2
+print len(prime_biggy(1000000))
+'''
+# from m to n
+def main(m, n):
+    primes = [False for x in xrange(n-m+1)]
+    p = 2
+    while p*p <= n:
+        r = m / p
+        r *= p
+        for j in xrange(r, n+1, p):
+            if j != p and j >= m:
+                primes[j-m] = True
+        p += 1
+ 
+    for i in xrange(n-m+1):
+        if not primes[i] and m+i != 1:
+            print m + i
+ 
+ 
+if __name__ == "__main__":
+    t = int(raw_input()) ## nb of test cases
+ 
+    for k in xrange(t):
+        m, n = map(int, raw_input().split())
+        main(m, n)
+        if k < t-1:
+            print ""
+'''