#include <bits/stdc++.h>
using namespace std;
unsigned long long popCount64bitB(unsigned long long x) {
  x = ((x & 0xaaaaaaaaaaaaaaaaUL) >> 1) + (x & 0x5555555555555555UL);
  x = ((x & 0xccccccccccccccccUL) >> 2) + (x & 0x3333333333333333UL);
  x = ((x & 0xf0f0f0f0f0f0f0f0UL) >> 4) + (x & 0x0f0f0f0f0f0f0f0fUL);
  x = ((x & 0xff00ff00ff00ff00UL) >> 8) + (x & 0x00ff00ff00ff00ffUL);
  x = ((x & 0xffff0000ffff0000UL) >> 16) + (x & 0x0000ffff0000ffffUL);
  x = ((x & 0xffffffff00000000UL) >> 32) + (x & 0x00000000ffffffffUL);
  return x;
}
int main(void) {
  int ans = 0;
  string s;
  cin >> s;
  int i = 0;
  if (s.length() == 1)
    ans = 1;
  else {
    string pre = "";
    for (int i = 0; i < s.length(); i++) {
      if (i + 2 == s.length()) {
        if (s[i] == s[i + 1]) {
          ans++;
          i += 2;
          continue;
        }
      }
      if (s.substr(i, 2) == pre) {
        pre = s.substr(i, 2);
        i++;
      } else {
        pre = s.substr(i, 1);
      }
      ans++;
    }
  }
  cout << ans << endl;
}
