using System;
class Program
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        int evenSum = 0;
        int oddSum = 0;

        for (int i = 0; i < n; i++)
        {
            int inputNumber = int.Parse(Console.ReadLine());
            if (i % 2 == 0)
            {
                evenSum += inputNumber;
            }
            else
            {
                oddSum += inputNumber;
            }
        }

        if (evenSum == oddSum)
        {
            Console.WriteLine("Yes sum= {0}", evenSum);
        }
        else
        {
            int diff = Math.Abs(evenSum - oddSum);
            Console.WriteLine("No diff= {0}", diff);
        }
    }
}