#include "bits/stdc++.h"
// Begin Header {{{
#define let             const auto
#define all(x)          (x).begin(), (x).end()
#define rep(i, n)       for (i64 i = 0, i##_limit = (n); i < i##_limit; ++i)
#define reps(i, s, t)   for (i64 i = (s), i##_limit = (t); i <= i##_limit; ++i)
#define repr(i, s, t)   for (i64 i = (s), i##_limit = (t); i >= i##_limit; --i)
#define var(Type, ...)  Type __VA_ARGS__; input(__VA_ARGS__)
#define lowerBound(...)                 _lowerBound(__VA_ARGS__)
#define upperBound(...)                 _upperBound(__VA_ARGS__)
#define _lowerBound(begin, end, ...)    (lower_bound((begin), (end), __VA_ARGS__) - (begin))
#define _upperBound(begin, end, ...)    (upper_bound((begin), (end), __VA_ARGS__) - (begin))

#ifdef DBG
#define trace(...) _trace(#__VA_ARGS__, __VA_ARGS__)
#else
#define trace(...)
#endif

using namespace std;
using i64 = int_fast64_t;
using pii = pair<i64, i64>;
template<class T> using MaxHeap = priority_queue<T>;
template<class T> using MinHeap = priority_queue<T, vector<T>, greater<T>>;
template<class T, class U>inline bool chmax(T &a, const U &b){return b>a && (a=b, true);}
template<class T, class U>inline bool chmin(T &a, const U &b){return b<a && (a=b, true);}
inline i64  sigma(i64 n)                    { return (n * (n + 1) >> 1); }
inline i64  divup(i64 a, i64 b)             { return (a + b - 1) / b; }
inline bool inner(i64 a, i64 low, i64 high) { return (low <= a && a <= high); }
inline string to_string(char c)             { return string(1, c); }
constexpr int INF  = 0x3f3f3f3f;
constexpr i64 LINF = 0x3f3f3f3f3f3f3f3fLL;

template<class T>
vector<T> makeVec(size_t sz) { return vector<T>(sz); }

template<class T, class... Args>
auto makeVec(size_t sz, Args... args) {
    return vector<decltype(makeVec<T>(args...))>(sz, makeVec<T>(args...));
}

template<class T>
inline void input(T &x) { cin >> x; }

template<class Head, class... Tail>
inline void input(Head &head, Tail&... tail) { cin >> head; input(tail...); }

inline void print() { cout << "\n"; }

template<class Head, class... Tail>
inline void print(Head &&head, Tail&&... tail) {
    cout << head;
    if (sizeof...(tail)) cout << ' ';
    print(forward<Tail>(tail)...);
}

template<class T>
ostream& operator<< (ostream &out, const vector<T> &vec) {
    static constexpr const char *delim[] = { " ", "" };
    for (const auto &e : vec) out << e << delim[&e == &vec.back()];
    return out;
}

template<class T>
ostream& operator<< (ostream &out, const vector<vector<T>> &mat) {
    static constexpr const char *tail[] = { "\n", "" };
    for (const auto &row : mat) out << row << tail[&row == &mat.back()];
    return out;
}

template <class T>
void _trace(const char *s, T&& x) {
    clog << '{';
    while(*s != '\0') clog << *(s++);
    clog << ":" << setw(3) << x << '}' << endl;
}

template <class Head, class... Tail>
void _trace(const char *s, Head&& head, Tail&&... tail) {
    clog << '{';
    while(*s != ',') clog << *(s++);
    clog << ":" << setw(3) << head << "}, ";
    for (++s; !isgraph(*s); ++s);
    _trace(s, std::forward<Tail>(tail)...);
}
// }}} End Header

signed main()
{
    ios::sync_with_stdio(false); cin.tie(nullptr);
    var(string, s);

    int res = 0;
    string prev = "";

    rep(i, s.length()) {
        string tmp = to_string(s[i]);
        if (tmp == prev) {
            if (i + 1 >= s.length()) break;
            tmp += s[++i];
        }
        prev = tmp;
        ++res;
    }

    print(res);


    return 0;
}


Measured memory_bytes: 720