#include<bits/stdc++.h>
using namespace std;
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define dbg(x) cout << #x << '=' << x << '\n';
#define ll long long
#define sz size()
#define x first
#define y second
#define pi pair <int, int>
#define pii pair <int, pi>
#define vi vector <int>
const ll mod = 1e9 + 7;
int n, d[100001], idx, mx;
vi g[100001];

void dfs(int node, int p){
    for(int i: g[node]){
        if(i!=p){
            d[i]=d[node]+1;
            if(mx<d[i]){
                idx=i;
                mx=d[i];
            }
            dfs(i, node);
        }
    }
}

int32_t main(){
    ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();
    ifstream cin("darb.in");
    ofstream cout("darb.out");
    cin>>n;
    for(int i=1; i<n; i++){
        int x, y;
        cin>>x>>y;
        g[x].pb(y);
        g[y].pb(x);
    }
    dfs(1, 0);
    mx=0;
    d[idx]=1;
    dfs(idx, 0);
    cout<<mx;
}