怎么改都过不了样例QAQWQVQAQWQVQAQWQVQ……
#include <bits/stdc++.h>
using namespace std;
int n, s, c[10005], y[10005];
long long ans;
int main() {
cin >> n >> s;
for (int i = 1; i <= n; i++) cin >> c[i] >> y[i];
for (int i = 1; i <= n; i++) {
long long sum = 0, money = 1005000;
for (int j = i; j >= 1; j--) {
sum += s;
money = min(money, sum + c[j]);
}
ans += money * y[i];
}
cout << ans;
return 0;
}