#include<cstdio>
#include<algorithm>
#include<map>
#include<cstring>
#include<cmath>
#include<iostream>
using namespace std;
typedef long long LL;

map<pair <string,string>,LL> cnt;
const int maxn = 50;
char s[maxn];

int main(){
	int n; scanf("%d",&n);
	scanf("%s",s);
	for(int i = 0;i < (1 << n);i++){
		string s1 = "",s2 = "";
		for(int j = 0;j < n;j++){
			if(i & (1 << j)) s1 += s[j];
			else s2 += s[j];
		}
		cnt[make_pair(s1,s2)]++;
	}
	LL sum = 0;
	for(int i = 0;i < (1 << n);i++){
		string s1 = "",s2 = "";
		for(int j = n - 1;j >= 0;j--){
			if(i & (1 << j)) s2 += s[j + n];
			else s1 += s[j + n];
		}
		sum += cnt[make_pair(s2,s1)];
	}
	printf("%lld\n",sum);
}