#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define Inf32 1000000001
#define Inf64 4000000000000000001

int main(){
    int n;
    cin >> n;
    vector<long long> a(n), b(n);
    for (int i = 0; i < n; ++i) cin >> a[i] >> b[i];
    long long as = 0, bs = 0;
    long long ans = 0;
    for (int i = n - 1; i >= 0; i--){
        ans += max(as * b[i], bs * a[i]);
        as += a[i];
        bs += b[i];
    }
    cout << ans << endl;
    return 0;
}