#include <iostream>
#include <algorithm>
using namespace std;

const int N = 100010;
typedef long long LL;
struct proj{
    int t,p; //排队时间和游玩时间
    bool operator<(const proj &w)const{
        return p < w.p;
    }
}Proj[N];
int n;
int main()
{
    cin >> n;
    for(int i = 1;i <= n;i ++) 
    {
        int x,y;
        cin >> x >> y;
        Proj[i] = {x,y};
    }

    sort(Proj + 1,Proj + n + 1);

    LL sum = 0;

    for(int i = 1;i <= n;i ++)
    {
        sum += Proj[i].t + (n - i + 1) * (LL)Proj[i].p;
    }
    cout << sum << endl;
    return 0;
}