TruckTour

namespace TruckTour
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;

    public class Startup
    {
        public static void Main()
        {
            Queue<GasPump> allGasPumps = new Queue<GasPump>();

            int numberOfInputs = int.Parse(Console.ReadLine());
            for (int currInputLine = 0; currInputLine < numberOfInputs; currInputLine++)
            {
                allGasPumps.Enqueue(new GasPump(currInputLine, Console.ReadLine()
                                                               .Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
                                                               .Select(int.Parse)
                                                               .ToArray()));
            }

            int countOfPumpsPassedBy = 0;
            int gasPumpsToStopBy = allGasPumps.Count;

            int totalGasoline = 0;

            while (countOfPumpsPassedBy != gasPumpsToStopBy)
            {
                GasPump gasPump = allGasPumps.Dequeue();

                totalGasoline += gasPump.Gasoline;

                if (totalGasoline >= gasPump.DistanceToTravel)
                {
                    totalGasoline -= gasPump.DistanceToTravel;

                    countOfPumpsPassedBy++;
                }
                else
                {
                    countOfPumpsPassedBy = 0;

                    totalGasoline = 0;
                }

                allGasPumps.Enqueue(gasPump);
            }

            Console.WriteLine(allGasPumps.Peek().Index);
        }
    }

    public class GasPump
    {
        private int gasoline;
        private int distanceToTravel;

        private int index;

        public GasPump(int index, params int[] gasPumpInfo)
        {
            this.gasoline = gasPumpInfo[0];
            this.distanceToTravel = gasPumpInfo[1];

            this.index = index;
        }

        public int Gasoline
        {
            get { return this.gasoline; }
            set { this.gasoline = value; }
        }

        public int DistanceToTravel
        {
            get { return this.distanceToTravel; }
            set { this.distanceToTravel = value; }
        }

        public int Index
        {
            get { return this.index; }
        }
    }
}