#include <fstream>
#include <vector>
#include <queue>
#define MaxN 100001
using namespace std;

int N, veg, t;
vector<int> sl[MaxN];
bool l[MaxN];
int tav[MaxN];

void Be()
{
    int x, y;
    ifstream f("darb.in");
    f>>N;
    for (int i=1;i<N;i++)
    {
        f>>x>>y;
        sl[x].push_back(y);
        sl[y].push_back(x);
    }
}

int bfs1()
{
    queue<int> q;
    q.push(1);
    l[1]=1;
    int fr;
    while (!q.empty())
    {
        fr=q.front();
        for (int i=0;i<sl[fr].size();i++)
        {
            if (!l[sl[fr][i]])
            {
                q.push(sl[fr][i]);
                l[sl[fr][i]]=1;
            }
        }
        veg=fr;
        q.pop();
    }
}

int bfs2()
{
    queue<int> q;
    q.push(veg);
    int fr;
    tav[veg]=1;
    while (!q.empty())
    {
        fr=q.front();
        for (int i=0;i<sl[fr].size();i++)
        {
            if (!tav[sl[fr][i]])
            {
                tav[sl[fr][i]]=tav[fr]+1;
                q.push(sl[fr][i]);
            }
        }
        if (tav[fr]>t)
            t=tav[fr];
        q.pop();
    }
}

void Ki()
{
    ofstream g("darb.out");
    g<<t;
}

int main()
{
    Be();
    bfs1();
    bfs2();
    Ki();
}