#include<bits/stdc++.h>
using namespace std;
int main(){
    int i=1,s=1,n;
    cin>>n;
    while(i<=n){
    s=s*i;
    i++;
    }
    cout<<s;
 
 
}
/**************************************************************
	Problem: 1004
	User: chenyichuen
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/