#include <bits/stdc++.h>
using namespace std;
using lint = long long;
int main() {
  lint n;
  cin >> n;
  vector<vector<lint>> dp(n+1, vector<lint>(n, -1));
  vector<lint> a(n), b(n);
  for (int i = 0; i < n; i++) cin >> a[i] >> b[i];
  reverse(a.begin(), a.end());
  reverse(b.begin(), b.end());
  dp[0][0] = 0;
  for (lint i = 0; i < n; i++) {
    for (lint j = 0; j < n; j++) {
      if (dp[i][j] == -1) continue;
      // a
      dp[i+1][j] = max(dp[i+1][j], dp[i][j]+j*a[i]);
      // b
      dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+b[i]);
    }
  }
  lint ans = 0;
  for (int j = 0; j <= n; j++) {
    ans = max(ans, dp[n][j]);
  }
  cout << ans << endl;
}