#include<bits/stdc++.h>
#include<fstream>

typedef unsigned long long ull;

using namespace std;

ifstream fin("fact.in");
ofstream fout("fact.out");

int main(){
int n,p=1,i;
fin>>n;
for(i=1;i<=n;i++)
p=p*i;
fout<<p;
	return 0;
}