func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 50100;   int n, l[MAXN], p[MAXN], idx[MAXN];   double ev[MAXN], el[MAXN];   int idxCMP(int i, int j) {     return p[i] * l[i] * (100 - p[j]) > p[j] * l[j] * (100 - p[i]);   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cin >> n;     for (int i = 0; i < n; i++) {       cin >> l[i] >> p[i];       idx[i] = i;     }     sort(idx, idx + n, idxCMP);     for (int i = 1; i <= n; i++) {       ev[i] =           ev[i - 1] + (el[i - 1] * (100 - p[idx[i - 1]]) / 100.0) + l[idx[i - 1]];       el[i] = el[i - 1] + l[idx[i - 1]] * p[idx[i - 1]] / 100.0;     }     cout << fixed << setprecision(10) << ev[n] << endl;   }   