using System;

public class Test
{
	public static void Main(){
     	int[] M = new int[10] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
     	int mul = 1;
     	int idx = 1;
        while (idx < M.Length) {
            mul *= M[idx]; 
            idx *= 2;
        }
		Console.WriteLine(mul);
	}
}