#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,s=1;
    cin>>a;
    for(int i=1;i<=a;i++){
        s*=i;
    }
    cout<<s;
    return 0;
}
/**************************************************************
	Problem: 1004
	User: xiaohongyi
	Language: C++
	Result: Accepted
	Time:17 ms
	Memory:2072 kb
****************************************************************/