#include <bits/stdc++.h>

using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");
#define NMAX 100005
int n,dist[NMAX],maxim;
vector<int>g[NMAX];
queue <int>q;
void bfs(int poz){
    q.push(poz);
    while(!q.empty()){
        int node=q.front();
        q.pop();
        for(auto y:g[node]){
            if(!dist[y]){
                dist[y]=dist[node]+1;
                q.push(y);
                maxim=max(maxim,dist[y]);
            }
        }
    }
}
int main()
{
    in>>n;
    for(int i=1;i<n;i++){
        int x,y;
        in>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    bfs(1);
    int node;
    for(int i=1;i<=n;i++){
        if(dist[i]==maxim)
            node=i;
    }
     memset(dist,0,sizeof(dist));
     while(!q.empty())
        q.pop();
     bfs(node);
     out<<maxim+1;
    return 0;
}