#include <bits/stdc++.h>
using namespace std;
using lint = long long;
using uint = unsigned int;
using ulint = unsigned long long;
using ldouble = long double;
using pii = pair<int, int>;
using pli = pair<lint, lint>;
using pdd = pair<double, double>;
using pld = pair<ldouble, ldouble>;
using v1i = vector<int>;
using v1li = vector<lint>;
using v2i = vector<vector<int>>;
using v2li = vector<vector<lint>>;
using v3i = vector<vector<vector<int>>>;
using v3li = vector<vector<vector<lint>>>;
using v1b = vector<bool>;
using v2b = vector<vector<bool>>;
using v3b = vector<vector<vector<bool>>>;
using v1c = vector<char>;
using v2c = vector<vector<char>>;
using v3c = vector<vector<vector<char>>>;
constexpr lint mod1 = 1e9 + 7;
constexpr lint mod2 = 998244353;
int main() {
  int a = 0;
  bool b = 0;
  string s, t = "AA";
  cin >> s;
  for (int i = 0; i < s.size(); ++i) {
    if (b) {
      b = 0;
      t += s[i];
      ++a;
    } else if (t.size() == 2) {
      t = to_string(s[i]);
      ++a;
    } else if (t != to_string(s[i])) {
      t = to_string(s[i]);
      ++a;
    } else {
      t = to_string(s[i]);
      b = 1;
    }
  }
  cout << a << endl;
  return 0;
}
