#include <stdio.h>
#include <string.h>
#include <vector>
#define MAX 100005
using namespace std;

int n, i, x, y, distmax, nodemax;
vector<int> l[MAX];
bool viz[MAX];

void dfs(int node, int dist);

int main(){
	freopen("darb.in", "r", stdin);
	freopen("darb.out", "w", stdout);
	scanf("%d", &n);
	for(i = 0; i < n; i++){
		scanf("%d%d", &x, &y);
		l[x].push_back(y);
		l[y].push_back(x);
	}
	dfs(1, 1);
	memset(viz, 0, n + 1);
	dfs(nodemax, 1);
	printf("%d\n", distmax);
	return 0;
}

void dfs(int node, int dist){
	viz[node] = 1;
	if(dist > distmax){
		distmax = dist;
		nodemax = node;
	}
	for(int i = 0; i < l[node].size(); i++)
		if(!viz[l[node][i]])
			dfs(l[node][i], dist + 1);
}