#include <stdio.h>
int factorial( int n ){
	if(n==1) return 1;
	if(n==0) return 1;
	else return factorial(n-1)*n*factorial(0);
}
int main(void) {
int n;
scanf("%d", &n);
printf("%dの階乗は%d\n", n, factorial(n));
return 0;
}