//
// Problem: Step Aerobics
// Solution by: MORI Shingo
// O(n)
//
// 
#include <stdio.h>
#include <assert.h>

int main() {
  int n;
  int test_case = 0;
  while (scanf("%d", &n) > 0 && n) {
    test_case++;
    int ans = 0;
    int state = 0;
    int next = 3;
    for (int i = 0; i < n; i++) {
      char c;
      int v = scanf(" %c %*c ", &c);
      assert(v == 1);
      int lr = (c == 'l') ? 1 : 0;
      state ^= (1 << lr);
      if (state == next) {
        ans++;
        next ^= 3;
      }
    }
    printf("%d\n", ans);
  }
  assert(test_case <= 150);
}