func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long int tes;     cin >> tes;     while (tes--) {       long long int n, m;       cin >> m >> n;       vector<pair<long long int, long long int>> arr(n);       for (long long int i = 0; i < n; i++) cin >> arr[i].first >> arr[i].second;       sort(arr.begin(), arr.end());       vector<long long int> flower(n);       vector<long long int> cum(n + 1);       for (long long int i = 0; i < n; i++) flower[i] = arr[i].first;       cum[n] = 0;       for (int i = n - 1; i >= 0; i--) cum[i] = cum[i + 1] + flower[i];       long long int ans, here, left;       ans = 0;       m--;       for (long long int i = 0; i < n; i++) {         here = 0;         long long int key = arr[i].second;         long long int ix =             (upper_bound(flower.begin(), flower.end(), key) - flower.begin());         if (ix < n - m) ix = n - m;         here = here + cum[ix];         left = m - (n - ix);         here = here + left * key;         if (i < ix)           here = here + arr[i].first;         else           here = here + key;         ans = max(ans, here);       }       cout << ans << endl;     }   }   