#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    string s;
    cin >> s;
    int ans = 0;
    for (int i = 0; i < n - 1; i++) {
      if (s[i] == s[i + 1]) {
        ans++;
      }
    }
    cout << (ans + 1) / 2 << endl;
  }
  return 0;
}
