#include <iostream>
#include <vector>
#include <unordered_map>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.precision(10);
    cout << fixed;

    int t;
    cin >> t;

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

        unordered_map<char, int> charCount;
        for (char c : s) {
            charCount[c]++;
        }

        int totalSwaps = 0;
        for (auto& entry : charCount) {
            int count = entry.second;
            if (count > 1) {
                totalSwaps += (count * (count - 1)) ;
            }
        }

        cout << totalSwaps << endl;
    }

    return 0;
}