#include <stdio.h>

int fact(int n)
{
	int kaijyou;
	kaijyou=1;
	scanf("%d",&n);
	for(n=n; n>0; n--)
	{
		kaijyou=kaijyou*n;
	}
	
	return kaijyou;
}

int main(void) {
	int n;
	printf("%d",fact(n));
	
	// your code goes here
	return 0;
}