#include <bits/stdc++.h>

using namespace std;

int main() {
    string s; cin >> s;
    int n = s.size();
    int k = n;
    for (int i = 0; i < n - 1; i++) {
        if (s[i] == s[i + 1]) {
            k--;
            i += 2;
        }
    }
    cout << k;
}