using System;

public class Program

{

    public static void Main()

    {

        int sum=0,num,last=0;

        for(int i=1;i<=10;i++)

        {

             num =int.Parse(Console.ReadLine());

            if(i<10)sum+=num;

            else

                last=num;

        }

        if(sum==last)Console.WriteLine("yes");

        else

            Console.WriteLine("no");

    }

}