#include <bits/stdc++.h>
using namespace std;
long long power(long long a, long long n) {
  a %= 1000000007;
  if (n == 1) return a;
  if (n == 0) return 1;
  if (n % 2)
    return (a * (power((a * a) % 1000000007, n / 2) % 1000000007)) % 1000000007;
  return power((a * a) % 1000000007, n / 2) % 1000000007;
}
const long long inf = (long long)1e18;
long long inverse(long long x) { return power(x, 1000000007 - 2) % 1000000007; }
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  string s;
  cin >> s;
  long long ans = 0;
  for (long long i = 0; i < (long long)s.size(); ++i) {
    ++ans;
    if (i - 1 >= 0 && s[i] == s[i - 1]) ++i;
  }
  cout << ans;
  return 0;
}
