Equal Pairs

using System;

class EqualPairs
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        double previousPairSum = 0;
        double currentPairSum = 0;
        double difference = 0;
        double biggestdifference = 0;

        for (int i = 0; i < n; i++)
        {
            double firstNumber = double.Parse(Console.ReadLine());
            double secondNumber = double.Parse(Console.ReadLine());

            if (i == 0)
            {
                    previousPairSum = firstNumber + secondNumber;
            }
                else
            {
                    currentPairSum = firstNumber + secondNumber;
                    difference = Math.Abs(currentPairSum - previousPairSum);
                    if (difference > biggestdifference)
                    {
                        biggestdifference = difference;
                    }
                previousPairSum = currentPairSum;
            }
            }

        if (biggestdifference  == 0)
        {
            Console.WriteLine("Yes, value ={0}", previousPairSum);
        }
        else
        {
            Console.WriteLine("No, maxdiff ={0}", biggestdifference);
        }
    }
}