func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   bool r[100], c[100];   int main() {     cin >> n;     vector<int> ans;     for (int i = 1; i <= n * n; i++) {       int x, y;       cin >> x >> y;       if (!r[x] && !c[y]) {         ans.push_back(i);         r[x] = true;         c[y] = true;       }     }     for (int i = 0; i < ans.size(); i++) {       cout << ans[i] <<    ;     }     cout << endl;     return 0;   }   