#include<bits/stdc++.h> using namespace std; int n,cnt,ans[15],a[15],b[25],c[15]; void dfs(int step) { if(step>n) ++cnt; for(int i=1;i<=n;i++) { if(!(a[i]||b[i-step+n]||c[step+i])) { a[i]=b[i-step+n]=c[step+i]=1; ans[step]=i; dfs(step+1); a[i]=b[i-step+n]=c[step+i]=0; } } } int main() { cin>>n; dfs(1); cout<<cnt; }