#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 inf 1000000000

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

const int mod=1e9+7;

int n,root,maxi,x,y,viz[100005],dist[100005];
vector<int>nod[100005];


void bfs(int s){
    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;
            }
        }
        q.pop();
    }
    for(int i=1;i<=n;i++){
        if(maxi<dist[i]){
            maxi=dist[i];
            root=i;
        }
    }
}

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