#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

int main(){
    int N;
    string S;
    cin >> N >> S;

    if (N < 5) {
        cout << 0 << endl;
        return 0;
    }

    int ans = 0;
    vector<int> index(N);
    for (int i = 0; i < N; ++i) index[i] = i;

    vector<bool> select(N, false);
    fill(select.end() - 5, select.end(), true);

    do {
        vector<int> comb;
        for (int i = 0; i < N; ++i) {
            if (select[i]) comb.push_back(index[i]);
        }

        sort(comb.begin(), comb.end());

        char a = S[comb[0]];
        char b = S[comb[1]];
        char c = S[comb[2]];
        char d = S[comb[3]];
        char e = S[comb[4]];

        if (a == c && b != a && d != a && e != a &&
            b != c && b != d && b != e &&
            d != e && d != c &&
            e != c){
            ans++;
        }

    } while (next_permutation(select.begin(), select.end()));

    cout << ans << endl;
    return 0;
}