using System;

namespace ConsoleApp19
{
    class Program
    {
        static void Main(string[] args)
        {
            int width = int.Parse(Console.ReadLine());
            int lenght = int.Parse(Console.ReadLine());
            int hight = int.Parse(Console.ReadLine());
            int total = lenght * width * hight;
            string command = "";
            int boxSum = 0;
            bool isEnought = false;

            while (!isEnought)
            {
                int box = int.Parse(Console.ReadLine());
                boxSum += box;
                command = Console.ReadLine();

                if (command == "done")
                {
                    break;
                }

                if (boxSum > total)
                {
                    isEnought = true;
                    break;
                }

            }

            if (isEnought)
            {
                Console.WriteLine("no");
            }

            else
            {
                Console.WriteLine("yes");
            }

        }
    }
}