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