#include<bits/stdc++.h>
#define de fprintf(stderr,"on-%d\n",__LINE__)
//#define int long long
#define fr(i,a,b) for(int i(a),end##i(b);i<=end##i;i++)
#define fd(i,a,b) for(int i(a),end##i(b);i>=end##i;i--)
#define vec vector<int>
using namespace std;
int n;
int a[100],mx[100],f[100];
bool check(){
	fr(i,2,n){
		if(a[i]>a[i-1])f[a[i]]=a[i-1];
		else{
			int x=a[i-1];
			while(x>a[i])x=f[x];
			if(x==1)return 0;
			f[a[i]]=f[x];
		}
	}
	return 1;
}
int ans;
signed main(){
#ifdef pig
	freopen("pig.in","r",stdin);
	freopen("pig.out","w",stdout);
#endif
	cin>>n;
	fr(i,1,n)a[i]=i;
	do{
		if(check())ans++;
	}while(next_permutation(a+2,a+n+1));
	cout<<ans;
	return 0;
}