#include <bits/stdc++.h>

using namespace std;

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

int n,m;
vector <int> mv[100005];
queue <int> q;
int viz[100005];

int BFS(int x){
    int i,aux;

    q.push(x);
    viz[x]=1;

    while(!q.empty()){
        x=q.front();
        q.pop();

        aux=x;

        for(i=0;i<mv[x].size();i++){
            if(!viz[mv[x][i]]){
                viz[mv[x][i]]=viz[x]+1;
                q.push(mv[x][i]);
            }
        }
    }

    return aux;
}

int main(){
    int i,x,y,v;

    fin>>n;

    for(i=1;i<n;i++){
        fin>>x>>y;
        mv[x].push_back(y);
        mv[y].push_back(x);
    }

    v=BFS(1);

    memset(viz,0,sizeof(viz));

    fout<<viz[BFS(v)];

    return 0;
}