#include<bits/stdc++.h>
using namespace std;

const int N=2e5+10;

char ch[N];

int main() {
	scanf("%s",ch+1);
	int l=strlen(ch+1);
	int Ans=1,opt=1;
	int i;
	for(i=2;i<=l;) 
		if(!opt) Ans++,i++,opt=1;
		else if(ch[i]!=ch[i-1]) Ans++,i++;else Ans++,i+=2,opt=0;
	if(i>l+1) Ans--;
	cout<<Ans<<endl;
}
		
			
		
	