#include <bits/stdc++.h>
using namespace std;
template <typename T>
void _dbg(const char* _s, T _h) {
  cerr << _s << " = " << _h << "\n";
}
template <typename T, typename... Ts>
void _dbg(const char* _s, T _h, Ts... _t) {
  int _b = 0;
  while (((_b += *_s == '(') -= *_s == ')') != 0 || *_s != ',') cerr << *_s++;
  cerr << " = " << _h << ",";
  _dbg(_s + 1, _t...);
}
const int64_t INF = static_cast<int64_t>(1e9) + 7;
const int64_t LINF = INF * INF;
const int MAXN = static_cast<int>(1e6) + 17;
void solve() {
  string second;
  cin >> second;
  int n = second.length();
  if (n == 1) {
    cout << "1\n";
    return;
  }
  vector<int> dp(n);
  dp[0] = 1;
  dp[1] = (second[0] != second[1]);
  for (int i = 2; i < n; ++i) {
    dp[i] = dp[i - 1] + (second[i] != second[i - 1]);
    if (dp[i - 2] + 1 > dp[i]) {
      second[i] = '#';
      dp[i] = dp[i - 2] + 1;
    }
  }
  cout << dp[n - 1];
}
int main() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios_base::sync_with_stdio(false);
  int q = 1;
  for (int i = 0; i < q; ++i) {
    solve();
  }
}
