public class FactTest {
    public static void main (String [] args) {
	int n = Test.fact(5);
	System.out.println(n);
    }
}

class Test {
    // a recursive function fact 
    public static int fact(int n) {
	// base case:
	if (n == 1) return 1;
	return n * fact(n - 1);
    }
}