func_code_string: #include <bits/stdc++.h>   using namespace std;   using ll = long long;   int main() {   y:     cin.tie(0);     cout.tie(0);     cin.sync_with_stdio(0);     ;     ll n = 0, k = 0;     cin >> n >> k;     ll a = 0, b = 0;     ll sum = 0;     ll pos = 0;     for (int i = 0; i < k; ++i) {       cin >> a >> b;       sum += b;       pos += a * b;     }     if (sum < n)       cout << 1 <<   n ;     else {       if (!(pos % n == (n * (n - 1)) / 2 % n))         cout << -1 <<   n ;       else         cout << 1 <<   n ;     }     return 0;   }   