#include <bits/stdc++.h>
using namespace std;
long long v[3001];
ifstream fin("nunta.in");
ofstream fout("nunta.out");
int main()
{unsigned long long n,s=1,p=1,i;
fin>>n;
for(i=1;i<=n;i++)s=s*i;
for(i=1;i<=n-p;i++)p=p*i;
fout<<s/p;
fin.close();
fout.close();
return 0;}