#include <fstream>
#include <vector>
#include <cstring>

using namespace std;

const int NMAX = 1e5 + 1;

bool viz[NMAX];
int n, diam, ult;
vector<int> G[NMAX];

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

void citire()
{
    int x, y;
    fin >> n;
    for(int i = 1; i < n; i++)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void dfs(int x, int niv)
{
    if(niv > diam)
    {
        diam = niv;
        ult = x;
    }
    viz[x] = 1;
    for(auto &y : G[x])
        if(!viz[y])
            dfs(y, niv + 1);
}
int main()
{
    citire();
    dfs(1, 1);
    memset(viz, 0, sizeof(viz));
    dfs(ult, 1);
    fout << diam;
    return 0;
}