using System;

public class Program

{

    public static void Main()

    {

        double size1, size2, size3;

        Console.WriteLine("size1, size2, size3");

        size1=double.Parse(Console.ReadLine());

        size2=double.Parse(Console.ReadLine());

        size3=double.Parse(Console.ReadLine());

        if((size1+size2>size3)&&(size1+size3>size2)&&(size2+size3>size1))

            Console.WriteLine("yes");

        else

            Console.WriteLine("no");

    }

}