#include<bits/stdc++.h>
using namespace std;
int n;
int main(){
   cin>>n;
   int ans=1;
   for (int i=1;i<=n;i++){
    ans=ans*i;
   }
   cout<<ans;
    
}
/**************************************************************
	Problem: 1004
	User: hongguangxi
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/