#include <fstream>
#include <vector>
#include <cstring>
#define pb push_back

using namespace std;

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

void DFS(int x, int dist);

int n, maxim, poz, uz[100005];
vector<int> L[100005];

int main()
{
    int i, x, y;

    fin >> n;
    for (i=1;i<n;i++)
    {
        fin >> x >> y;
        L[x].pb(y);
        L[y].pb(x);
    }
    DFS(1,1);
    memset(uz,0,sizeof(uz));
    DFS(poz,1);
    fout << maxim << '\n';
    return 0;
}

void DFS(int x, int dist)
{
    int i;

    uz[x] = 1;
    if (dist > maxim)
    {
        maxim = dist;
        poz = x;
    }
    for (i=0;i<L[x].size();i++)
        if (!uz[L[x][i]])
            DFS(L[x][i],dist+1);
}