#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, i, ans = 0;
    cin >> n;
    string s;
    cin >> s;
    for (i = 0; i < n - 1; i++) {
      if (s[i] == s[i + 1]) {
        ans++;
      }
    }
    cout << ceil(ans / 2.0) << endl;
  }
  return 0;
}
