func_code_string: #include <bits/stdc++.h>   using namespace std;   using lint = long long int;   int main() {     lint n;     cin >> n;     vector<lint> v(n);     for (lint i = 0; i < n; i++) {       cin >> v[i];     }     lint val = 2 * accumulate(v.begin(), v.end(), 0ll) / n;     vector<lint> visited(n);     for (lint i = 0; i < n; i++) {       if (visited[i]) {         continue;       }       for (lint j = i + 1; j < n; j++) {         if (visited[j]) {           continue;         }         if (v[i] + v[j] == val) {           visited[i] = 1;           visited[j] = 1;           cout << (i + 1) <<     << (j + 1) << endl;           break;         }       }     }   }   