#include<bits/stdc++.h>
using namespace std;
int main()
{int n,i=1,s=1;
cin>>n;
while(i<=n){
s=s*i,i++;

}
cout<<s;
	return 0;
}

/**************************************************************
	Problem: 1004
	User: sf751616
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/