#include <iostream>
#include<map>

using namespace std;

int main() {
    int t;
    cin >> t;
    while (t--) {
        int n;
        cin>>n;
        string str;
        cin>>str;

        map<char,int> freq;
        for (char c : str) {
            freq[c]++;
        }

        long long result = 0;
        for (auto p : freq) {
            int count = p.second;
            if (count > 1) {
                result += count * (count - 1);
            }
        }
        cout << result << endl;
    }
    return 0;
}