#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    vector<pair<long long,long long>> AB(N);
    for(auto &[a,b] : AB) cin >> a >> b;
 
    vector<long long> dp(N+1);
    for(auto [a,b] : AB){
        vector<long long> next(N+1);
        for(int k=0; k<=N; k++){
            if(k) next.at(k-1) = max(next.at(k-1),dp.at(k)+b);
            next.at(k) = max(next.at(k),dp.at(k)+a*k);
        }
        swap(dp,next);
    }

    cout << dp.at(0) << endl;
}