using System;

public class Test
{
	public static void Main()
	{
		int[] data = new int[] { 1, 2, 0, 3, 4, 5, 6, 7, 0, 8, 9 };
		
		bool is_multiplied = false;
		long result = 0;
		
		int index = 0;
		while (index < data.Length)
		{
			if (data[index] == 0)
			{
				is_multiplied = !is_multiplied;
				
				if (!is_multiplied)
				{
					break;
				}
				
				result = 1;
			}
			else
			{
				if (is_multiplied)
				{
					result *= data[index];
					
				}
			}
			
			index++;
		}
		
		Console.WriteLine(result);
	}
}