05. Bus

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _05.Bus
{
    class Program
    {
        static void Main(string[] args)
        {

            int countPassengers = int.Parse(Console.ReadLine());
            int busStops = int.Parse(Console.ReadLine());

           // int count = 1;
            int sumPassengers = 0;
            int ednPassengers = 0;

            for (int i = 1; i <= busStops; i++)
            {
                int outPassengers = int.Parse(Console.ReadLine());
                int inPassengers = int.Parse(Console.ReadLine());

                if (i % 2 != 0)
                {
                    sumPassengers -= outPassengers;
                    sumPassengers += inPassengers + 2;
                }
                else
                {
                    sumPassengers -= outPassengers;
                    sumPassengers += inPassengers - 2;
                }
            }
            ednPassengers = countPassengers + sumPassengers;
            Console.WriteLine($"The final number of passengers is : {ednPassengers}");
        }
    }
}