import java.util.Scanner;

public class library_sathvik {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int testCases = scan.nextInt();

        for(int tt = 0; tt < testCases; tt++) {
            int n = scan.nextInt();
            char[] author = scan.next().toCharArray();
            int[] freq = new int[26];
            long ans = 0;

            for(int i = 0; i < n; i++) {
                int curr = author[i] - 'a';
                for(int j = curr + 1; j < 26; j++) {
                    ans += freq[j];
                }
                freq[curr]++;
            }
            System.out.println(ans);
        }
    }
}