Equal Pairs fixed

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

namespace pairs
{
    class Program
    {
        static void Main(string[] args)
        {

            var number = double.Parse(Console.ReadLine());


            double sum = 0;
            double sum2 = 0;
            double max = 0;
            double avg = 0;




            for (int i = 1; i <= number; i++)
            {
                sum2 = sum;
                var a = double.Parse(Console.ReadLine());
                var b = double.Parse(Console.ReadLine());

                sum = a + b;

                if (i == 1)
                {
                   continue;
                }
                avg = Math.Abs(sum - sum2);

                if (avg > max)
                    {
                        max = avg;
                    }

            }


            if (max == 0)
            {
                Console.WriteLine("Yes, value={0}", sum);
            }
            else
            {

                Console.WriteLine("No, maxdiff={0}",max);
            }
        }
    }
}