#include <bits/stdc++.h>

using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
struct arb
{
    vector <int> v;
};
arb a[100001];
int c1[100001];
int c2[100001];
queue< int > q;
int main()
{int n,i,j,k;
f>>n;
for(k=1;k<n;k++)
{
    f>>i>>j;
    a[i].v.push_back(j);
    a[j].v.push_back(i);
}
q.push(1);
c1[1]=1;
while(!q.empty())
{
    k=q.front();
    q.pop();
    for(i=0;i<a[k].v.size();i++)
        if(!c1[a[k].v[i]])
        {
            c1[a[k].v[i]]=1+c1[k];
            q.push(a[k].v[i]);
        }
}
q.push(k);
c2[k]=1;
while(!q.empty())
{
    k=q.front();
    q.pop();
    for(i=0;i<a[k].v.size();i++)
        if(!c2[a[k].v[i]])
        {
            c2[a[k].v[i]]=1+c2[k];
            q.push(a[k].v[i]);
        }
}
g<<*max_element(c2+1,c2+n+1);

    return 0;
}