public class Factorial
{
	public static void main (String args [ ])
	{

		System.out.println(factorial());
		int holder = in.nextInt();
		Scanner in = new Scanner(System.in);
	}
}


class mo dito

{
	public int factorial (int n)
		{
			if(n<=1) return 1;

			else return n*factorial(n-1);
		}



}