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

            dist[g[node][i]]=dist[node]+1;
            dfs(g[node][i]);
        }
}