func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t, m, n, a, ans;     cin >> t;     while (t--) {       ans = 0;       cin >> n >> m;       for (int i = 0; i < n; i++) {         cin >> a;         ans += a;       }       if (n > m || n == 2)         cout <<  -1  << endl;       else {         cout << 2 * ans << endl;         for (int i = 1; i < n; i++) {           cout << i <<     << i + 1 << endl;         }         cout <<  1  <<     << n << endl;       }     }     return 0;   }   