a.cpp

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

#define vec vector 
#define ll long long
#define all(v) (v).begin(), (v).end()
#define nl << "\n"


const ll MOD = 1e9 + 7;
const ll INF = 1e9;



void solve() {
    int n; cin >> n;
    int ans = 0;
    string s; cin >> s;
    for (int i = 1; i < n - 1;){
        if (s[i] == s[i - 1]){
            i++;
            continue;
        }

        if (s[i - 1] == s[i + 1]){
            ans++;
            char t = s[i];
            s[i] = s[i + 1];
            s[i + 1] = t;
            i+= 2;

        }else {
        i+= 1;
        }

    }

    cout << ans nl;





}

int main () {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int tc = 1;
    cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t << ": ";
        solve();
    }

}