func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( O3 )   using namespace std;   using ll = long long;   using ull = unsigned long long;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     ll n;     int k;     cin >> n >> k;     ll s = n * (n - 1) / 2;     s %= n;     ll t = 0;     ll cnt = 0;     for (int i = 0; i < k; i++) {       ll a, b;       cin >> a >> b;       (t += a * b) %= n;       cnt += b;     }     if (cnt < n) {       cout <<  1 n ;     } else if (cnt > n) {       cout <<  -1 n ;     } else {       if (s == t) {         cout <<  1 n ;       } else {         cout <<  -1 n ;       }     }     return 0;   }   