#include <bits/stdc++.h>
#define MAX 100010
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector <int>g[MAX];
queue <int>co;
bool uz[MAX];
int dist[MAX];
int maxim,pct,n;
void bfs(int node);
void citire();
int main()
{
    citire();
    bfs(1);
    maxim=0;
    memset(uz,0,sizeof(uz));
    memset(dist,0,sizeof(dist));
    bfs(pct);
    fout<<maxim+1;
    return 0;
}
void citire()
{
    int i,x,y;
    fin>>n;
    for(i=1; i<n; i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }

}
void bfs(int node)
{
    int nodecrt,i;
    uz[node]=1;
    co.push(node);
    while(!co.empty())
    {
        nodecrt=co.front();
        co.pop();
        if(dist[nodecrt]>maxim)
        {
            maxim=dist[nodecrt];
            pct=nodecrt;
        }
        for(i=0; i<g[nodecrt].size(); i++)
            if(uz[g[nodecrt][i]]==0)
            {
                co.push(g[nodecrt][i]);
                uz[g[nodecrt][i]]=1;
                dist[g[nodecrt][i]]=dist[nodecrt]+1;
            }
    }
}