#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<array<int, 2>> a(n);
for (auto &[x, y] : a) {
cin >> x >> y;
}
sort(a.begin(), a.end());
i64 ans = 0;
auto cdq = [&](auto && self, int l, int r)->void{
if (l == r)
return ;
int mid = l + r >> 1;
self(self, l, mid);
self(self, mid + 1, r);
sort(a.begin() + l, a.begin() + mid + 1, [](auto x, auto y) {
if (x[1] != y[1]) return x[1] < y[1];
return x[0] < y[0];
});
sort(a.begin() + mid + 1, a.begin() + r + 1, [](auto x, auto y) {
if (x[1] != y[1]) return x[1] < y[1];
return x[0] < y[0];
});
int sum1 = 0, sum2 = 0;
for (int i = l; i <= mid; i ++)
sum1 += a[i][1];
int i = l, j = mid + 1;
while (j <= r) {
while (i <= mid && a[i][1] < a[j][1]) {
sum1 -= a[i][1], sum2 += a[i][1];
i ++;
}
int cnt1 = i - l, cnt2 = mid - i + 1;
ans += 1ll * a[j][0] * (cnt1 * a[j][1] - sum2 + sum1 - cnt2 * a[j][1]);
j ++;
}
};
cdq(cdq, 0, n - 1);
cout << ans << '\n';
return 0;
}