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

void solve(){
    int n;
    cin>>n;
    string s;
    cin>>s;
    int i, j, op = 0;
    for(i=0;i<n;i++){
        for(j=0;j<n-1;j++){
            if((s[j]-'0')<(s[j+1]-'0')){
               swap(s[j],s[j+1]);
               op++;
            }
        }
    }

    cout<<op<<endl;
}

int main(){
    int t;
    cin>>t;
    while(t--){
        solve();
    }

    return 0;
}