#include<stdio.h>
#include <string.h> 

#include<vector>

using namespace std;
#define MAXN 100000

int M,N;

vector<int> L[MAXN];
unsigned char visited[MAXN]; // vector pentru marcarea nodurilor

int lastNode;

int maxLength;

void depth(int nod,int length){
	// procesarea nodului de indice nod
	visited[nod]=1;
	if(length>maxLength){
		maxLength=length;
		lastNode=nod;
	}
	vector<int>::iterator it; 
	for (it = L[nod].begin(); it != L[nod].end(); ++it) {
		if(visited[*it]==0)
			depth(*it,length+1);	
	}
}

int main(){
	freopen("darb.in","rt",stdin);
	freopen("darb.out","wt",stdout);

	scanf("%d",&N);

	int x,y;
	int nb=0;

	for(int i=0;i<(N-1);i++){
		scanf("%d %d",&x,&y);
		L[x-1].push_back(y-1);	
		L[y-1].push_back(x-1);
	}

	depth(0,1);

	memset(visited,0,N);
	maxLength=0;

	depth(lastNode,1);

	printf("%d\n",maxLength);
	return 0;
}