#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e18;

int N,a,b;
int A[5050];
int B[5050];


int f(int n,int atk){
    if(n == N){
        return atk == 0 ? 0:-INF;
    }
    int ret;
    // 攻撃しない
    ret = f(n+1,atk) + A[n] * atk;
    // 攻撃する
    if(atk > 0)ret = max(ret, f(n+1,atk-1) + B[n]);

    return ret;
}

signed main(){
    cin >> N;
    for (int i = 0;i < N;i++)
    {
        cin >> A[i] >> B[i];
    }

    int ans = 0;
    for(int i = 1;i <= N;i++)
    {
        ans = max(ans, f(0,i));
    }
    cout << ans << endl;
    return 0;
}