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

class TruckTour
    {
    static void Main( )
        {
        long stops = long.Parse(Console.ReadLine());
        Queue<string> myQueue = new Queue<string>();

        for ( long i = 0;i < stops;i++ )
            {
            myQueue.Enqueue( Console.ReadLine( ) );
            }

        bool canMakeIt= false;


        for ( long i = 0;i < stops;i++ )
            {
            long fuel = 0;
            foreach ( var item in myQueue )
                {
                fuel += item.Trim( ).Split( new char[] { ' ' },StringSplitOptions.RemoveEmptyEntries ).Select( long.Parse ).ToArray( )[0];
                fuel -= item.Trim( ).Split( new char[] { ' ' },StringSplitOptions.RemoveEmptyEntries ).Select( long.Parse ).ToArray( )[1];
                if ( fuel <=0 )
                    {
                    canMakeIt = false;
                    break;
                    }
                else
                    {
                    canMakeIt = true;
                    }
                }
            if ( canMakeIt )
                {
                Console.WriteLine(i);
                return;
                }
            string helper = myQueue.Dequeue();
            myQueue.Enqueue( helper );

            }
        }
    }