#include<iostream>

#include<cstdio>

#include<cstring>

#include<cstdlib>

#include<string>

#include<cmath>

#include<ctime>

#include<algorithm>

#include<map>

#include<set>

#include<queue>

#include<iomanip>

using namespace std;

#define ll long long

#define db double

#define up(i,j,n) for(int i=j;i<n;i++)

#define pii pair<int,int>

#define uint unsigned int

#define FILE "dealing"

int read(){

	int x=0,f=1,ch=getchar();

	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}

	while(ch>='0'&&ch<='9'){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}

	return x*f;

}

template<class T> bool cmax(T& a,T b){return a<b?a=b,true:false;}

template<class T> bool cmin(T& a,T b){return a>b?a=b,true:false;}

const int maxn=4100,limit=128,inf=1000000000;

int a[maxn],n;

int fac[15];

int ans;

void Swap(int a[],int b[],int len){

	up(i,0,len)swap(a[i],b[i]);

}

void dfs(int pos,int cnt){

	if(pos==n){

		ans+=fac[cnt];

		return;

	}

	int top=0,q[3]={0,0,0};int len=1<<pos+1;

	for(int i=0;i<1<<n;i+=len){

		if(a[i+(len>>1)-1]+1!=a[i+(len>>1)]){

			if(top==2)return;

			q[++top]=i;

		}

	}

	if(top==0){

		dfs(pos+1,cnt);

		return;

	}

	if(top==1){

		int i=q[1];

		if(a[i+len-1]+1==a[i]){

			Swap(a+i,a+i+(len>>1),len>>1);

			dfs(pos+1,cnt+1);

			Swap(a+i,a+i+(len>>1),len>>1);

		}

		return;

	}

	if(top==2){

		int i=q[1],j=q[2];

		if(a[i+(len>>1)]==a[j+(len>>1)-1]+1&&a[j+(len>>1)]==a[i+(len>>1)-1]+1){

			Swap(a+i,a+j,len>>1);

			dfs(pos+1,cnt+1);

			Swap(a+i,a+j,len>>1);

			Swap(a+i+(len>>1),a+j+(len>>1),len>>1);

			dfs(pos+1,cnt+1);

			Swap(a+i+(len>>1),a+j+(len>>1),len>>1);

		}

		if(a[i]==a[j+(len>>1)-1]+1&&a[j+(len)-1]+1==a[i+(len>>1)]){

			Swap(a+i,a+j+(len>>1),len>>1);

			dfs(pos+1,cnt+1);

			Swap(a+i,a+j+(len>>1),len>>1);

		}

		if(a[j]==a[i+(len>>1)-1]+1&&a[i+(len)-1]+1==a[j+(len>>1)]){

			Swap(a+j,a+i+(len>>1),len>>1);

			dfs(pos+1,cnt+1);

			Swap(a+j,a+i+(len>>1),len>>1);

		}

		return;

	}

}

int main(){

	freopen(FILE".in","r",stdin);

	freopen(FILE".out","w",stdout);

	n=read();

	fac[0]=1;

	up(i,1,n+1)fac[i]=fac[i-1]*i;

	up(i,0,1<<n)a[i]=read();

	dfs(0,0);

	printf("%d\n",ans);

	return 0;

}