#include <bits/stdc++.h>
using namespace std;
int cnt, n;
string ss;
int main() {
  cin >> n >> ss;
  for (int i = 0; i < n; i++) {
    if (i < n - 1 && ((ss[i] == 'R' && ss[i + 1] == 'U') ||
                      (ss[i] == 'U' && ss[i + 1] == 'R'))) {
      i++;
      cnt++;
    } else
      cnt++;
  }
  cout << cnt << endl;
}
