#include<bits/stdc++.h>
using namespace std;
int main()
{
int n;
cin>>n;
int i=1,q=1;
while(i<=n){
   q*=i;
   i++;
}

cout<<q<<endl; 
	return 0;
}

/**************************************************************
	Problem: 1004
	User: czr
	Language: C++
	Result: Accepted
	Time:18 ms
	Memory:2072 kb
****************************************************************/