#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <iomanip>
#include <numeric>
using namespace std;
using ll = long long;
int main() {
	int N;cin >> N;
	vector<ll> A(N), B(N);
	for (int i = 0;i < N;i++) cin >> A[i] >> B[i];
	vector<ll> dp(N+1, -1);
	dp[0] = 0;
	for (int i = N-1;i >= 0;i--) {
		vector<ll> ndp(N+1, -1);
		for (int j = 0;j <= N;j++) {
			if (dp[j] < 0) continue;
			//use a
			ndp[j] = max(ndp[j], dp[j] + ((ll)j * A[i]));
			//useb
			if (j+1 <= N) ndp[j+1] = max(ndp[j+1], dp[j] + B[i]);
		}
		swap(dp, ndp);
	}
	ll res = 0;
	for (int i = 0;i <= N;i++) res = max(res, dp[i]);
	cout << res << endl;
}