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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, ans = 0;
    string s;
    cin >> n >> s;
    constexpr int nt = (1 << 6) - 1;
    for(int S = (1 << 5) - 1; S < (1 << n); ){
        int U = 0, T = S, x = S & (-S), y = S + x;
        for(int j = 0; j < 5; j++){
            int b = T & -T;
            char c = s[__lg(b)];
            if(j == 2 && s[__lg(x)] != c){
                U = nt;
                break;
            }
            U |= 1 << c - 'A';
            T ^= b;
        }
        ans += __builtin_popcount(U) == 4;
        S = ((S & ~y) / x >> 1) | y;
    }
    cout << ans << '\n';
}