#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int res = 0;
  for (int i = 0; i < n; i++) {
    res++;
    if (i == n - 1) break;
    if (s[i] != s[i + 1]) {
      i++;
    }
  }
  cout << res << "\n";
}
