#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int n = s.length();
  int i = 0;
  int k = 0;
  int last = 0;
  while (i < n - 1) {
    int j = i;
    if (s[j] != s[j + 1]) {
      k++;
      i = j + 1;
    } else {
      while (s[j] == s[j + 1] && j < n - 1) j++;
      if (j - i + 1 > 2)
        k = k + (j - i + 1) / 2 + 1;
      else
        k++;
      last = j - i + 1;
    }
    i = j + 1;
  }
  if (last > 2) k--;
  cout << k + 1 << endl;
  return 0;
}
