#include <bits/stdc++.h>
using namespace std;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr long long LINF = numeric_limits<long long>::max() / 3;
struct Double {
  double d;
  explicit Double(double x) : d(x) {}
};
ostream& operator<<(ostream& os, const Double x) {
  os << fixed << setprecision(20) << x.d;
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& vec) {
  os << "[";
  for (const auto& v : vec) {
    os << v << ",";
  }
  os << "]";
  return os;
}
template <typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const set<T>& st) {
  os << "{";
  for (T v : st) os << v << ",";
  os << "}";
  return os;
}
template <typename T, typename U>
inline void chmax(T& x, U y) {
  if (y > x) x = y;
}
template <typename T, typename U>
inline void chmin(T& x, U y) {
  if (y < x) x = y;
}
long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
constexpr double eps = 1e-10;
constexpr long long mod = 1e9 + 7;
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
int n;
void solve() {
  int ans = 0;
  vector<string> vs(n);
  for (int i = 0; i < n; i++) cin >> vs[i];
  for (int i = 0; i < n; i += 2) {
    string s1 = vs[i];
    string s2 = vs[i + 1];
    if (s1 == "lu" and s2 == "ru")
      ans++;
    else if (s1 == "ru" and s2 == "lu")
      ans++;
    else if (s1 == "ld" and s2 == "rd")
      ans++;
    else if (s1 == "rd" and s2 == "ld")
      ans++;
  }
  cout << ans << endl;
}
int main() {
  while (1) {
    cin >> n;
    if (n == 0) break;
    solve();
  }
}
