#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
const ll MAX_N = 2e5;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    ll n; cin >> n;
    vector<ll> a(n+1), b(n+1); for(ll i=1; i<=n; i++) cin >> a[i] >> b[i];

    vector<ll> a_lsum(n+2, 0), a_rsum(n+2, 0), b_lsum(n+2, 0), b_rsum(n+2, 0);
    for(ll i=1; i<=n; i++){
        a_lsum[i] = a_lsum[i-1]+a[i];
        b_lsum[i] = b_lsum[i-1]+b[i];
    }
    for(ll i=n; i>=1; i--){
        a_rsum[i] = a_rsum[i+1]+a[i];
        b_rsum[i] = b_rsum[i+1]+b[i];
    }

    vector<ll> p_lsum(n+2, 0), p_rsum(n+2, 0);
    ll L=1, R=n;
    ll ans = 0;
    for(ll i=1; i<=n; i++){
        //左に置いた場合の寄与
        ll lans = 0;
        lans += a[i]*p_lsum[L-1];
        lans += b[i]*(a_rsum[i+1]+p_rsum[R+1]);


        //右に置いた場合の寄与
        ll rans = 0;
        rans += a[i]*(p_lsum[L-1]+b_rsum[i+1]);
        rans += b[i]*p_rsum[R+1];

        if(lans < rans){
            ans += rans;
            p_rsum[R]=p_rsum[R+1]+a[i];
            R--;
        }else{
            ans += lans;
            p_lsum[L]=p_lsum[L-1]+b[i];
            L++;
        }
    }

    cout << ans/2 << endl;
}