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