diff --git a/Codechef/DEM2020/PhoneNumberLetterCombinations.cpp b/Codechef/DEM2020/PhoneNumberLetterCombinations.cpp
new file mode 100644
index 0000000..ac75ab9
--- /dev/null
+++ b/Codechef/DEM2020/PhoneNumberLetterCombinations.cpp
@@ -0,0 +1,39 @@
+#include<iostream>
+using namespace std;
+
+int solve(string digits, int index, string maping_values[], string output){
+    // base case
+    if(digits.length() == output.length()){
+        cout << output << endl;
+        return 0;
+    }
+    int digit = digits[index] - '0';
+    string char_digits = maping_values[digit];
+    for(int i=0;i<char_digits.length();i++){
+        output.push_back(char_digits[i]);
+        solve(digits, index+1, maping_values, output);
+        output.pop_back();
+    }
+    return 0;
+}
+
+
+int main() {
+    string digits;
+    cin >> digits;
+    string maping_values[] = {"", "", "abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
+    solve(digits, 0, maping_values, "");
+    return 0;
+/*
+23
+ad
+ae
+af
+bd
+be
+bf
+cd
+ce
+cf
+*/
+}