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