#include <bits/stdc++.h>   using namespace std;   int main() {     cin.tie(NULL);     cout.tie(NULL);     ios_base::sync_with_stdio(false);     long long int n, i, t, k, c, s = 0, x, sum = 0, st1 = 0, st2 = 0, curr = 0;     cin >> n;     vector<pair<long long int, long long int> > v;     vector<long long int> p;     for (i = 0; i < n; i++) {       cin >> k >> c;       v.push_back(make_pair(c, k));     }     cin >> t;     for (i = 0; i < t; i++) {       cin >> x;       s = x;       p.push_back(s);     }     p.push_back(100000000000000);     sort(v.begin(), v.end());     while (st1 < n) {       if (curr + v[st1].second < p[st2]) {         sum += (st2 + 1) * (v[st1].first) * (v[st1].second);         curr += v[st1].second;         st1++;       } else {         long long int rem = p[st2] - curr;         curr += rem;         sum += (rem) * (st2 + 1) * (v[st1].first);         v[st1].second -= rem;         st2++;         if (!v[st1].second) {           st1++;         }       }     }     cout << sum;   }   