#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
typedef struct node
{
	char data;
	struct node *L_Child,*R_Child;
}Tree;
void initTree(Tree *&T)
{
	char str;
	cin>>str;
	if(str!='#')
	{
		T=(Tree *)malloc(sizeof(Tree));
		T->data=str;
		initTree(T->L_Child);//先序遍歷就是前序遍歷，從左節點開始遍歷
		initTree(T->R_Child);
	}
	else T=NULL;
}
int Deepth_of_Tree(Tree *&T)
{
	if(T==NULL) return 0;
	else
	{
		int sum1=0,sum2=0;
		sum1=Deepth_of_Tree(T->L_Child);//左鏈的長度;
		//cout<<"sum1="<<sum1<<" "<<"now"<<endl;
		sum2=Deepth_of_Tree(T->R_Child);//右鏈的長度;
		//cout<<"sum2="<<sum2<<" "<<"now"<<endl;
		if(sum1>sum2) return sum1+1;
		else return sum2+1;
	}
} 
int main()
{
	Tree *T;
	initTree(T);
	int num=Deepth_of_Tree(T);
	cout<<num;
	return 0;
}