#include <bits/stdc++.h>
//#define int long long
#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 mp make_pair
#define el cout<<'\n'
#define rc(s) return cout<<s,0
//#define cin fin
//#define cout fout
using namespace std;

#define MAX_N 1000001
#define inf 1000000000

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

const int mod=1e9+7;

int n,root,maxi,x,y,viz[MAX_N],dist[MAX_N];
vector<int>nod[MAX_N];


void bfs(int s){
    memset(viz,0,MAX_N);
    memset(dist,0,MAX_N);
    maxi=0;
    queue<int>q;
    viz[s]=1;
    q.push(s);
    while(!q.empty()){
        s=q.front();
        for(auto it:nod[s]){
            if(!viz[it]){
                viz[it]=1;
                q.push(it);
                dist[it]=dist[s]+1;
                maxi=dist[it];
            }
        }
        if(q.size()==1) root=s;
        q.pop();
    }
}

int32_t main(){
    ios_base::sync_with_stdio(0);cin.tie();cout.tie();
    fi >> n;
    for(int i=1;i<n;i++){
        fi >> x >> y;
        nod[x].pb(y);
        nod[y].pb(x);
    }
    bfs(1);
    bfs(root);
    maxi++;
    fo<<maxi<<'\n';
}