#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define mp make_pair
#define si(x) int(x.size())
const int mod=998244353,MAX=300005,INF=1<<30;

int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int N;cin>>N;
    vector<ll> A(N+1),B(N+1);
    for(int i=0;i<N;i++) cin>>A[i]>>B[i];
    for(int i=N-1;i>=0;i--){
        A[i]+=A[i+1];
        B[i]+=B[i+1];
    }
    
    ll ans=0;
    
    for(int i=0;i<N;i++){
        ll x=(A[i]-A[i+1])*B[i+1];
        ll y=(B[i]-B[i+1])*A[i+1];
        ans+=max(x,y);
    }
    
    cout<<ans<<endl;
}