#include<cstdio>
#include<cstring>
int len,ans;
char S[200100];
int main(){
	scanf("%s",S+1);len=strlen(S+1);
	int now=1;
	while(now<=len){
		ans++,now++;
		while(S[now]!=S[now-1]&&now<=len)ans++,now++;
		if(now>=len)break;
		ans++,now+=2;
	}
	printf("%d\n",ans);
}