#include <bits/stdc++.h>
using namespace std;
template <typename _KTy, typename _Ty>
ostream& operator<<(ostream& o, const pair<_KTy, _Ty>& m) {
  o << "{" << m.first << ", " << m.second << "}";
  return o;
}
template <typename _KTy, typename _Ty>
ostream& operator<<(ostream& o, const map<_KTy, _Ty>& m) {
  if (m.empty()) {
    o << "{ }";
    return o;
  }
  o << "{" << *m.begin();
  for (auto itr = ++m.begin(); itr != m.end(); itr++) {
    o << ", " << *itr;
  }
  o << "}";
  return o;
}
template <typename _KTy, typename _Ty>
ostream& operator<<(ostream& o, const unordered_map<_KTy, _Ty>& m) {
  if (m.empty()) {
    o << "{ }";
    return o;
  }
  o << "{" << *m.begin();
  for (auto itr = ++m.begin(); itr != m.end(); itr++) {
    o << ", " << *itr;
  }
  o << "}";
  return o;
}
template <typename _Ty>
ostream& operator<<(ostream& o, const vector<_Ty>& v) {
  if (v.empty()) {
    o << "{ }";
    return o;
  }
  o << "{" << v.front();
  for (auto itr = ++v.begin(); itr != v.end(); itr++) {
    o << ", " << *itr;
  }
  o << "}";
  return o;
}
template <typename _Ty>
ostream& operator<<(ostream& o, const set<_Ty>& s) {
  if (s.empty()) {
    o << "{ }";
    return o;
  }
  o << "{" << *(s.begin());
  for (auto itr = ++s.begin(); itr != s.end(); itr++) {
    o << ", " << *itr;
  }
  o << "}";
  return o;
}
template <typename _Ty>
ostream& operator<<(ostream& o, const unordered_set<_Ty>& s) {
  if (s.empty()) {
    o << "{ }";
    return o;
  }
  o << "{" << *(s.begin());
  for (auto itr = ++s.begin(); itr != s.end(); itr++) {
    o << ", " << *itr;
  }
  o << "}";
  return o;
}
template <typename _Ty>
ostream& operator<<(ostream& o, const stack<_Ty>& s) {
  if (s.empty()) {
    o << "{ }";
    return o;
  }
  stack<_Ty> t(s);
  o << "{" << t.top();
  t.pop();
  while (!t.empty()) {
    o << ", " << t.top();
    t.pop();
  }
  o << "}";
  return o;
}
template <typename _Ty>
ostream& operator<<(ostream& o, const list<_Ty>& l) {
  if (l.empty()) {
    o << "{ }";
    return o;
  }
  o << "{" << l.front();
  for (auto itr = ++l.begin(); itr != l.end(); ++itr) {
    o << ", " << *itr;
  }
  o << "}";
  return o;
}
template <typename _KTy, typename _Ty>
istream& operator>>(istream& is, pair<_KTy, _Ty>& m) {
  is >> m.first >> m.second;
  return is;
}
template <typename _Ty>
istream& operator>>(istream& is, vector<_Ty>& v) {
  for (size_t i = 0; i < v.size(); i++) is >> v[i];
  return is;
}
namespace aux {
template <typename Ty, unsigned N, unsigned L>
struct tp {
  static void print(ostream& os, const Ty& v) {
    os << get<N>(v) << ", ";
    tp<Ty, N + 1, L>::print(os, v);
  }
};
template <typename Ty, unsigned N>
struct tp<Ty, N, N> {
  static void print(ostream& os, const Ty& v) { os << get<N>(v); }
};
}  // namespace aux
template <typename... Tys>
ostream& operator<<(ostream& os, const tuple<Tys...>& t) {
  os << "{";
  aux::tp<tuple<Tys...>, 0, sizeof...(Tys) - 1>::print(os, t);
  os << "}";
  return os;
}
template <typename A, size_t N, typename T>
inline void Fill(A (&array)[N], const T& val) {
  std::fill((T*)array, (T*)(array + N), val);
}
void dump_func() { std::cerr << std::endl; }
template <class Head, class... Tail>
void dump_func(Head&& head, Tail&&... tail) {
  std::cerr << head;
  if (sizeof...(Tail) == 0) {
    std::cerr << " ";
  } else {
    std::cerr << ", ";
  }
  dump_func(std::move(tail)...);
}
template <typename Ty>
Ty modpow(Ty n, Ty e, Ty m) {
  Ty result = 1;
  while (e > 0) {
    if (e & 1) result = (result * n) % m;
    e >>= 1;
    n = (n * n) % m;
  }
  return result;
}
class timer {
 public:
  double t = 0;
  timer() {}
  void measure() { t = time() - t; }
  static double time() {
    unsigned long long a, d;
    __asm__ volatile("rdtsc" : "=a"(a), "=d"(d));
    return (d << 32 | a) / 2.8e9;
  }
} timer;
struct Xorshift {
  uint64_t x = 88172645463325252LL;
  unsigned nextUInt() {
    x = x ^ (x << 7);
    return x = x ^ (x >> 9);
  }
  unsigned nextUInt(unsigned mod) {
    x = x ^ (x << 7);
    x = x ^ (x >> 9);
    return x % mod;
  }
  unsigned nextUInt(unsigned l, unsigned r) {
    x = x ^ (x << 7);
    x = x ^ (x >> 9);
    return x % (r - l + 1) + l;
  }
  double nextDouble() { return double(nextUInt()) / UINT_MAX; }
} rnd;
int solve(string S) {
  S = "#" + S;
  int n = S.size();
  int ans = 0, prev = 1;
  for (int i = 1; i < n; i++) {
    if (prev == 1) {
      if (S[i] == S[i - 1]) {
        prev = 2;
        i++;
      }
    } else {
      prev = 1;
    }
    ans++;
  }
  if (n >= 2 && S[n - 1] == S[n - 2]) ans--;
  return ans;
}
int main() {
  timer.measure();
  cin.tie(0);
  ios::sync_with_stdio(false);
  string S;
  cin >> S;
  cout << solve(S) << endl;
  return 0;
}
