func_code_string: #include <bits/stdc++.h>   using namespace std;   int v, e;   vector<int> out[30005];   vector<int> ans;   bool vis[30005];   void dfstree(int n) {     for (auto x : out[n]) {       if (!vis[x]) {         vis[x] = true;         dfstree(x);       }     }     ans.push_back(n);   }   int main() {     cin >> v >> e;     for (int i = 0; i < e; i++) {       int x, y;       cin >> x >> y;       out[x].push_back(y);     }     for (int i = 1; i < v + 1; i++) {       if (!vis[i]) {         vis[i] = true;         dfstree(i);       }     }     for (auto x : ans) cout << x <<    ;     cout <<   n ;     ;   }   