#include <bits/stdc++.h>   const int MAXN = 50 + 10;   bool row[MAXN];   bool column[MAXN];   int main() {     int n, x, y;     std::cin >> n;     for (int i = 0; i <= n * n; i++) {       std::cin >> x >> y;       if (row[x - 1] == false && column[y - 1] == false) {         row[x - 1] = true;         column[y - 1] = true;         std::cout << i + 1 <<    ;       }     }     return 0;   }   