01.StacksAndQueue-07.TruckTour

using System;
using System.Collections.Generic;
using System.Linq;

namespace _07.TruckTour
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            Queue<int[]> pumps = new Queue<int[]>();

            for (int i = 0; i < n; i++)
            {
                int[] input = Console.ReadLine().Split().Select(int.Parse).ToArray();

                pumps.Enqueue(input);
            }

            int counter = 0;

            while (true)
            {
                int myFuel = 0;

                bool theOne = true;
                for (int i = 0; i < n; i++)
                {

                    int[] currentPump = pumps.Peek();
                    int currentFuel = currentPump[0];
                    int distanceToNextPump = currentPump[1];

                    if (myFuel + currentFuel < distanceToNextPump)
                    {
                        theOne = false;
                    }

                    myFuel += currentFuel;
                    myFuel -= distanceToNextPump;
                    pumps.Dequeue();
                    pumps.Enqueue(currentPump);
                }
                if (theOne)
                {
                    break;
                }
                counter++;
                pumps.Enqueue(pumps.Dequeue());
            }
            Console.WriteLine(counter);
        }
    }
}