#include<bits/stdc++.h>
using namespace std;

int n,ans;

string str;

string kill(string a, int k, int j){
	string op = "";
	for(int i = 0; i < a.length(); i++){
		if(i!=k && i != j) op+=a[i];
	}
	return op;
}

void back(string p){
	if(p == ""){
		ans++;
		return;
	}
	for(int i = 0; i < p.length(); i++){
		if(p[i] == p[i+1]){
			p = kill(p,i,i+1);
			back(p);
			p = "";
		}
	}
}

int main()
{
//	freopen("game.in","r",stdin);
//	freopen("game.out","w",stdout);
	cin>>n>>str;
	for(int i = 2; i <= str.length(); i+=2)
	for(int k = 0; k <= str.length() && k+i<=str.length(); k++){
		string a = "";
		for(int j = k; j < i+k; j++) a+=str[j];
		back(a);
	}
	cout<<ans;
	return 0;
}

学c++学了没多久赛时写的蒟蒻代码，请问如果这种思路能不能优化