#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long a[1005], b[1005], n, i, j, k, temp, sum;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    cin >> b[i];
  }
  for (i = 0; i < n - 1; i++) {
    for (j = 0; j < n - i - 1; j++) {
      if (b[j] > b[j + 1]) {
        temp = b[j];
        b[j] = b[j + 1];
        b[j + 1] = temp;
        temp = a[j];
        a[j] = a[j + 1];
        a[j + 1] = temp;
      } else if (b[j] == b[j + 1]) {
        if (a[j] > a[j + 1]) {
          temp = a[j];
          a[j] = a[j + 1];
          a[j + 1] = temp;
        }
      }
    }
  }
  sum = 0;
  k = 1;
  for (i = n - 1; i >= 0; i--) {
    if (k > 0) {
      sum += a[i];
      k -= 1;
    }
    k += b[i];
    if (k == 0) break;
  }
  cout << sum << endl;
  return 0;
}
