#include <bits/stdc++.h>

using namespace std;

ifstream in("darb.in");
ofstream out("darb.out");

int n, m, mx, x, y;
vector <int> v[100100];
bool viz[100100];

void dfs(int from, int lvl){
	if(lvl > mx){
		mx = lvl;
		x = from;
	}
	viz[from] = 1;
	for(auto to : v[from])
		if(!viz[to])
			dfs(to, lvl + 1);
}

int main(){
	in >> n;
	for(int i = 1; i < n; i++){
		in >> x >> y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	dfs(1, 1);
	memset(viz, 0, sizeof viz);
	dfs(x, 1);
	out << mx;
	return 0;
}