import java.util.*;

public class Main{
    
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        
        String S = sc.next();
        sc.close();

        int index = 0;
        int count = 0;
        while(index < S.length()-1){
            if(S.charAt(index) != S.charAt(index+1)){
                index++;
                count++;
                if(index == S.length()-1)
                    count++;
            } else {
                if(index != S.length()-2) {
                    count += 2;
                    index += 3;
                } else {
                    count++;
                    index += 2;
                }
            }
        }
        System.out.println(count);
    }
}