#include <bits/stdc++.h> using namespace std; typedef long long ll; const ll N=1e5+1e4,M=1e3+1e2; const ll Maxn=0x3ffffff,Minm=-0x3ffffff; ll n,ans=1; signed main() { cin>>n; for(ll i=1;i<=n;i++)ans*=i; cout<<ans; }