#include <bits/stdc++.h>
#include <stdio.h>
#include <string.h>
#define ll long long
#define all(a) (a).begin(), (a).end()
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define sz() size()
#define fr first
#define sc second
#define pb push_back
#define er erase
#define in insert
#define pi pair<int,int>
#define pii pair<pair<int,int>,int>
#define mp make_pair
//#define int long long
#define rc(s) return cout<<s,0
#define rcc(s) cout<<s,exit(0)
///#define cin fin
///#define cout fout
using namespace std;
 
const int mod=1e9+7;

int n,x,y,dist[100005];
vector<int>nod[100005];
bitset<100005>viz;
 
int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
    srand(chrono::steady_clock::now().time_since_epoch().count());
    ifstream fin("darb.in");
    ofstream fout("darb.out");
    fin >> n;
    for(int i=1;i<n;i++){
        fin >> x >> y;
        nod[x].push_back(y);
        nod[y].push_back(x);
    }
    queue<int>q;
    int root=1;
    viz[root]=1;
    q.push(root);
    int x=0;
    while(!q.empty()){
        x=q.front();
        for(auto it:nod[x]){
            if(!viz[it]){
                viz[it]=1;
                dist[it]=dist[x]+1;
                q.push(it);
            }
        }
        q.pop();
    }
    for(int i=1;i<=n;i++){
        if(dist[root]<dist[i]) root=i;
    }
    for(int i=1;i<=n;i++){
        dist[i]=0,viz[i]=0;
    }
    viz[root]=1;
    q.push(root);
    while(!q.empty()){
        x=q.front();
        for(auto it:nod[x]){
            if(!viz[it]){
                viz[it]=1;
                dist[it]=dist[x]+1;
                q.push(it);
            }
        }
        q.pop();
    }
    fout << dist[x]+1 << '\n';
}