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