#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001

int main(){
	
	int n;
	cin>>n;
	vector<long long> a(n),b(n);
	rep(i,n)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;
}