func_code_string: #include <bits/stdc++.h>   using namespace std;   struct inf {     long long v;     long long b;   };   bool cmp(struct inf a, struct inf c) { return a.b > c.b; }   int main() {     struct inf a[300005];     long long n, k, i, j, sum = 0, ans = -1, temp;     cin >> n >> k;     for (i = 0; i < n; i++) {       cin >> a[i].v >> a[i].b;     }     sort(a, a + n, cmp);     priority_queue<long long, vector<long long>, greater<long long>> q;     for (i = 0; i < n; i++) {       if (i < k) {         sum += a[i].v;         q.push(a[i].v);         ans = max(ans, sum * a[i].b);       } else {         temp = q.top();         if (temp < a[i].v) {           sum -= temp;           q.pop();           q.push(a[i].v);           sum += a[i].v;           ans = max(ans, sum * a[i].b);         }       }     }     cout << ans;     return 0;   }   