#include <iostream>
using namespace std;

int main() {
  int n, count, result = 0;
  long double cost;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> count >> cost;
    if (cost < 50) {
      result += count;
    }
  }
  cout << result;
  return 0;
}