diff --git a/Appendix E/solutions/21276.cpp b/Appendix E/solutions/21276.cpp
index 6c991660..f2b0766f 100644
--- a/Appendix E/solutions/21276.cpp	
+++ b/Appendix E/solutions/21276.cpp	
@@ -1,11 +1,62 @@
-// Authored by : BaaaaaaaaaaarkingDog
+// Authored by : uhwan0723
 // Co-authored by : -
-// http://boj.kr/****************
+// http://boj.kr/e2d7dbb7a5544968a61c8d7dfaaffd97
 #include <bits/stdc++.h>
 using namespace std;
 
+int n, m;
+map<string, vector<string>> adj, childs; // adj[name] = name의 모든 후손들, childs[name] = name의 자식들
+map<string, int> indeg;
+map<string, string> par; // par[name] = name의 1대 조상
+vector<string> names;
+queue<string> q;
+
 int main(void){
   ios::sync_with_stdio(0);
   cin.tie(0);
+
+  cin >> n;
+  string s;
+  for(int i = 0; i < n; ++i){
+    cin >> s;
+    names.push_back(s);
+  }
+  sort(names.begin(), names.end());
+  cin >> m;
+  while(m--){
+    string ch, anc;
+    cin >> ch >> anc;
+    adj[anc].push_back(ch);
+    ++indeg[ch];
+  }
+
+  // 큐에 들어간 indegree가 0인 정점들 = 각 가문의 시조들
+  for(string name : names)
+    if(indeg[name] == 0) q.push(name);
+  cout << q.size() << '\n';
+  for(int i = 0; i < q.size(); ++i){
+    string name = q.front(); q.pop();
+    cout << name << ' ';
+    q.push(name);
+  }
+  cout << '\n';
+  
+  while(!q.empty()){
+    string cur = q.front(); q.pop();
+    for(string nxt : adj[cur]){
+      // nxt의 par[nxt]값은 여러 번 갱신될 수 있으나, nxt의 1대 조상이 큐에 들어갈 때 마지막으로 갱신된다.
+      par[nxt] = cur;
+      if(--indeg[nxt] == 0) q.push(nxt);
+    }
+  }
+  
+  for(string name : names)
+    childs[par[name]].push_back(name);
   
-}
\ No newline at end of file
+  for(string name : names){
+    cout << name << ' ' << childs[name].size() << ' ';
+    for(string ch : childs[name])
+      cout << ch << ' ';
+    cout << '\n';
+  }
+}