3 Equal numbers

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

namespace _3_Equal_Numbers
{
    class Program
    {
        static void Main(string[] args)
        {
            double n1 = double.Parse(Console.ReadLine());
            double n2 = double.Parse(Console.ReadLine());
            double n3 = double.Parse(Console.ReadLine());
            double n = n1 - n2 - n3;

            if (n == -n1)
            {
                Console.WriteLine("yes");
            }
            else
            {
                Console.WriteLine("no");
            }
            }
    }
}