#include<fstream>
using namespace std;
ifstream fin("factorial.in");
ofstream fout("factorial.out");
int n,p;
int main()
{
	p=1;
	fin>>n;
	for(int i=1;i<=n;++i)
	{
		p*=i;
	}
	fout<<p;
	fin.close();
               fout.close();
	return 0;
}