#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000086, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];

int a[N], b[N];
ll f[5086];
int main() {
    cin >> n;
    for (int i = 1; i < n + 1; i++) scanf("%d%d", a + i, b + i);
    memset(f, -0x3f, sizeof f);
    f[0] = 0;
    for (int i = n; i; i--) {
        for (int j = n; j >= 0; j--) {
            f[j] += (ll)j * a[i];
            if (j) f[j] = max(f[j], f[j - 1] + b[i]);
        }
    }
    ll res = 0;
    for (int i = 0; i <= n; i++) res = max(res, f[i]);
    printf("%lld\n", res);
    return 0;
}