/*
#include<cstdio>
#define syy myson
using namespace std;
int n,lie[21]={0},ans,i;
void search(int x)
{
	if(x>n)
	{
		ans++;
		return;
	}
	for(i=1;i<=n;i++)
	{
		if(!lie[i]) 
		{
			lie[i]=1;
			search(x+1);
			lie[i]=0;
		}
	}
}
int Main()
{
	//freopen("rook.in","r",stdin);freopen("rook.out","w",stdout);
	scanf("%d",&n);
	search(1);
	printf("%d",ans);
	return 0;
}
int main(){;}
int syy=Main();
*/
#include<cstdio>
#define syy myson
using namespace std;
int n,i;
long long ans=1;
int Main()
{
	freopen("rook.in","r",stdin);freopen("rook.out","w",stdout);
	scanf("%d",&n);
	for(i=1;i<=n;i++)ans*=i;
	printf("%lld",ans);
	return 0;
}
int main(){;}
int syy=Main();