#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define pii pair<int, int>

using namespace std;
double pi = acos(-1);
const int N = 2e5 + 10;
int n;
pii a[N];
bool cmp(pii x, pii y)
{
    return x.first * y.second < y.first * x.second;
}
main()
{
    cin >> n;
    for(int i = 0; i < n; i++) cin >> a[i].first >> a[i].second;

    sort(a, a + n, cmp);
    int mx = -1;
    bool ok = 0;
    int cur = 0;
    int cy = 0;
    for(int i = 0; i < n; i++)
    {
        if(abs(cur) > mx)
        {
            mx = abs(cur);
            if(cur < 0)
            {
                ok = 1;
            } else ok = 0;
        }
        cur += (cy + (cy + a[i].second)) * a[i].first;
        cy += a[i].second;
    }
    if(abs(cur) > mx)
        {
            mx = abs(cur);
            if(cur < 0)
            {
                ok = 1;
            } else ok = 0;
        }
    if(ok) cout << "-";
    cout << mx;
}