#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int d[100005], viz[100005];
vector <int> h[100005];
int n, m;
void Read()
{
    int x, y;
    fin >> n;
    for(int i = 1; i < n; i++)
        {
            fin >> x >> y;
            h[x].push_back(y);
            h[y].push_back(x);
        }
}

void DFS(int k)
{
    viz[k] = 1;
    for(auto i : h[k])
        if(viz[i] == 0)
    {
        d[i] = d[k] + 1;
        DFS(i);
    }
}


int main()
{
    int dist = 0, x;
    Read();
    DFS(1);
    for(int i = 1; i <= n; i++)
        if(dist < d[i])
        {
            dist = d[i];
            x = i;
        }

    for(int i = 1; i <= n; i++)
        d[i] = 0, viz[i] = 0;

    DFS(x);
    for(int i = 1; i <= n; i++)
        if(dist < d[i]) dist = d[i];

    fout << dist + 1;
    return 0;
}