import java.util.Scanner;

public class FactorialExample {
	
	public static double factorial(int n) {
		if (n<=1) return 1;
		return n*factorial(n-1);
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.print("Enter a number: ");
		int value = sc.nextInt();
		System.out.println(factorial(value));
		sc.close();
	}

}


//Copyright 2016 Evan Golub