#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
struct ss {
	string a, b;
	bool operator < (ss o) const {
		return tie(a, b) < tie(o.a, o.b);
	}
};

int N;
string str;
map<ss, ll> cnt;

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	
	cin >> N;
	cin >> str;
	
	for (int mask = 0; mask < (1<<N); mask++) {
		string x, y;
		for (int i = 0; i < N; i++) {
			if (mask & (1<<i)) x += str[i];
			else y += str[i];
		}
		cnt[{x, y}]++;
	}
	
	ll ans = 0;
	for (int mask = 0; mask < (1<<N); mask++) {
		string x, y;
		for (int i = 0; i < N; i++) {
			if (mask & (1<<i)) x += str[2*N-1-i];
			else y += str[2*N-1-i];
		}
		ans += cnt[{x, y}];
	}
	cout << ans << "\n";
	
	return 0;
}
