func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, m;   long long sum = 0;   int main() {     scanf( %lld%lld , &n, &m);     long long max_add = (n - 1) * n / 2;     long long min_add;     if (n % 2) min_add = (n / 2 + 1) * (n / 2);     if (n % 2 == 0) {       long long a1 = (n / 2 + 1) * (n / 2) / 2;       long long a2 = (n / 2 - 1) * (n / 2) / 2;       min_add = a1 + a2;     }     for (int i = 1; i <= m; i++) {       long long x, d;       scanf( %lld%lld , &x, &d);       sum += x * n;       if (d >= 0)         sum += (long long)d * max_add;       else         sum += (long long)d * min_add;     }     double ans = sum / 1.0;     ans = ans / n;     printf( %.15lf , ans);     return 0;   }   