#include <iostream>
#include <fstream>
using namespace std;

ifstream fin("fact.in");
ofstream fout("fact.out");

void fact(int a){
	int i=1, fact=1;
	while(i<=a)
	{
		fact=fact*i;
		i++;
	}
	fout<<fact;
}

int main()
{
	int P;
	fin >> P;
	fact(P);

	return 0;
}