ALL

#include <iostream>
using namespace std;

struct Node{int key;Node* left;Node*right;
Node(int k):key(k),left(NULL),right(NULL){}
};

class BinTree{
	Node* root_;
public:
	BinTree(){root_=NULL;}
	Node* getRoot(){return root_;}
	void insert(int k){
		Node* node=new Node(k);
		Node* pre=NULL;
		Node* post=root_;
		while(post!=NULL)
		{
			pre=post;
			if(k<=post->key)
				post=post->left;
			else
				post=post->right;
		}
		if(pre==NULL)
			root_=node;
		else if(k<=pre->key)
			pre->left=node;
		else
			pre->right=node;

		}

	int height(Node* tree)
	{
		int hLeft;
		int hRight;
		if(tree==NULL)
			return 0;
		hLeft=height(tree->left);
		hRight=height(tree->right);

		int max;
		if(hLeft>hRight)
			max=hLeft;
		else
			max=hRight;
		return 1 + max;
	}

};


int main()
{
	BinTree s1;
	int h;
	int N;
	int k;
	cin>> N;
	for(int i=0;i<N;i++)
	{
		cin>>k;
		s1.insert(k);
	}

	h=s1.height(s1.getRoot());
	cout<<h<<endl;
}