public class TruckTour {
  public Queue<int> PPQueue;
  public void TakeInput() {
    PPQueue = new Queue<int>();
    int n = int.Parse(Console.ReadLine());

    while (n-- > 0) {
      string[] tokens = Console.ReadLine().Split();
      PPQueue.Enqueue(int.Parse(tokens[0]) - int.Parse(tokens[1]));
    }
  }

  // get 0 based index of starting Petrol Pump
  public int GetStartingPumpIndex() {
    // start with an initial queue
    // start index is 0
    // keep popping items
    //  whenever it fails forward it to the next tage..
    int pass_count = 0;
    int s_fa = 0;
    int pp_start_index = 0;
    while (pass_count < PPQueue.Count) {
      int r_fa = PPQueue.Dequeue();   // residue of fuel amount
      s_fa += r_fa;
      if (s_fa < 0) {
        s_fa = 0;
        pp_start_index += pass_count + 1;
        pass_count = 0;
      }
      else pass_count++;
      PPQueue.Enqueue(r_fa);
    }
    return pp_start_index;
  }
}