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// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
// #pragma GCC optimize("unroll-loops")    
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <deque>
#include <cassert>
#include <iomanip> 
#include <chrono>
#define pb push_back
#define x first
#define y second
#define mp make_pair
#define files(FILENAME) read(FILENAME); write(FILENAME)
#define read(FILENAME) freopen((string(FILENAME) + ".in").c_str(), "r", stdin)
#define write(FILENAME) freopen((string(FILENAME) + ".out").c_str(), "w", stdout)
using namespace std;
        
template<typename T1, typename T2>inline void chkmin(T1 &x, T2 y) { if (x > y) x = y; }
template<typename T1, typename T2>inline void chkmax(T1 &x, T2 y) { if (x < y) x = y; } 
template<typename T, typename U> inline ostream &operator<< (ostream &_out, const pair<T, U> &_p) { _out << _p.first << ' ' << _p.second; return _out; }
template<typename T, typename U> inline istream &operator>> (istream &_in, pair<T, U> &_p) { _in >> _p.first >> _p.second; return _in; }
template<typename T> inline ostream &operator<< (ostream &_out, const vector<T> &_v) { if (_v.empty()) { return _out; } _out << _v.front(); for (auto _it = ++_v.begin(); _it != _v.end(); ++_it) { _out << ' ' << *_it; } return _out; }
template<typename T> inline istream &operator>> (istream &_in, vector<T> &_v) { for (auto &_i : _v) { _in >> _i; } return _in; }
template<typename T> inline ostream &operator<< (ostream &_out, const set<T> &_s) { if (_s.empty()) { return _out; } _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) { _out << ' ' << *_it; } return _out; }
template<typename T> inline ostream &operator<< (ostream &_out, const multiset<T> &_s) { if (_s.empty()) { return _out; } _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) { _out << ' ' << *_it; } return _out; }
template<typename T> inline ostream &operator<< (ostream &_out, const unordered_set<T> &_s) { if (_s.empty()) { return _out; } _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) { _out << ' ' << *_it; } return _out; }
template<typename T> inline ostream &operator<< (ostream &_out, const unordered_multiset<T> &_s) { if (_s.empty()) { return _out; } _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) { _out << ' ' << *_it; } return _out; }
template<typename T, typename U> inline ostream &operator<< (ostream &_out, const map<T, U> &_m) { if (_m.empty()) { return _out; } _out << '(' << _m.begin()->first << ": " << _m.begin()->second << ')'; for (auto _it = ++_m.begin(); _it != _m.end(); ++_it) { _out << ", (" << _it->first << ": " << _it->second << ')'; } return _out; }
template<typename T, typename U> inline ostream &operator<< (ostream &_out, const unordered_map<T, U> &_m) { if (_m.empty()) { return _out; } _out << '(' << _m.begin()->first << ": " << _m.begin()->second << ')'; for (auto _it = ++_m.begin(); _it != _m.end(); ++_it) { _out << ", (" << _it->first << ": " << _it->second << ')'; } return _out; }
 
typedef long double base;        
typedef pair<int, int> point;

map<pair<string, string>, long long> mem;

long long solve(string a, string pref) {
	if (a.size() < pref.size()) return 0;
	if (a.size() == 0 && pref.size() == 0) {
		return 1;
	}
	if (mem.count({a, pref})) {
		return mem[{a, pref}];
	}
	string nxt = string(a.begin() + 1, a.end());
	long long ans = 0;
	if (pref.size() && a[0] == pref.back()) {
		pref.pop_back();
		ans += solve(nxt, pref);
		pref += a[0];
	}
	string res = pref;
	while (nxt.size()) {
		if (nxt.back() == a[0]) {
			nxt.pop_back();
			ans += solve(nxt, pref);
			nxt += a[0];
		}
		pref = nxt.back() + pref;
		nxt.pop_back();
	}
	if (res.size() == 0) ans <<= 1;
	return mem[{a, res}] = ans;
}

int n;
string s;

int main() {
	ios::sync_with_stdio(0);
	srand(time(0));
	//read("input");
	cin >> n >> s;
	cout << solve(s, "") << endl;
}

Measured memory_bytes: 384