#include <fstream>
#include <vector>
#include <algorithm>
#define DIM 100002

using namespace std;

ifstream f("darb.in");
ofstream g("darb.out");

int n, t[DIM], viz[DIM], x, y, maxim, k, nodMax;

vector <int> arb[DIM];

bool cmp(int a, int b)
{
    return a > b;
}

void dfs(int nod, int niv)
{
    viz[nod] = 1;
    if(niv > maxim)
    {
        maxim = niv;
        nodMax = nod;
    }
    for(int i = 0; i < arb[nod].size(); ++ i)
    {
        int nodc = arb[nod][i];
        if(viz[nodc] == 0)
        {
            dfs(nodc, niv + 1);
        }
    }
}

int main()
{
    f>>n;
    for(int i = 1; i < n; ++ i)
    {
        f>>x>>y;
        arb[x].push_back(y);
        arb[y].push_back(x);
    }

    dfs(1, 1);

    maxim = 0;

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

    dfs(nodMax, 1);

    g<<maxim;

    return 0;
}