#include <bits/stdc++.h>
#define pb push_back
using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");
vector< vector<int> > tree;
vector<int> v;
int n,last;
void df(int x)
{
    for(vector<int>::iterator i=tree[x].begin();i!=tree[x].end();i++)
    if(v[*i]==-1)
    {
        v[*i]=v[x]+1;
        if(v[*i]>v[last])last=*i;
        df(*i);
    }
}
int main()
{
    in>>n;
    tree=vector< vector<int> >(n+1);
    for(int i=1;i<n;i++)
    {
        int x,y;
        in>>x>>y;
        tree[x].pb(y);
        tree[y].pb(x);
    }
    v=vector<int>(n+1,-1);
    v[1]=1;
    df(1);
    v=vector<int>(n+1,-1);
    v[last]=1;
    df(last);
    out<<v[last]<<'\n';
    return 0;
}