#include <iostream>
#include <queue>
#include <vector>
#include <cstring>
#include <cstdio>
#define N 1000005

using namespace std;

vector <int> a[N];
queue <int> q;
int n, dist[N], u;

void citire()
{
    scanf("%d\n", &n);
    for(int i=1;i<=n-1;i++)
    {
        int x, y;
        scanf("%d %d\n", &x, &y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

void bfs(int st)
{
   memset(dist, 0, sizeof(dist));
   q.push(st);
   dist[st]=1;
   while(!q.empty())
   {
       int nod=q.front();
       for(int i=0;i<a[nod].size();i++)
       {
           int nod2=a[nod][i];
           if(!dist[nod2])
           {
               q.push(nod2);
               dist[nod2]=dist[nod]+1;
               u=nod2;
           }
       }
       q.pop();
   }
}

int main()
{
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);

    citire();
    bfs(1);
    bfs(u);
    printf("%d", dist[u]);
    return 0;
}