#include<bits/stdc++.h>
using namespace std;
int main()
{
    int s,n,i;
    cin>>n;
	s=1;
	for(i=1;i<=n;i++) 
    {
    s*=i;	
    	
    	
    }
    cout<<s;    
	return 0;
}

/**************************************************************
	Problem: 1004
	User: LYY001
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/