#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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


const int N = 100001;

int n, niv = 0, nivmax = 0, xmax, dmax = 0;
int nivel[N], d[N];
bool ok[N];
vector<int> a[N];
queue<int> q;


void dfs(int x)
{
    ok[x] = 1;
    nivel[x] = ++niv;

    if(niv > nivmax)
    {
        nivmax = niv;
        xmax = x;
    }

    for(size_t i = 0; i < a[x].size(); i++)
    {
        int y = a[x][i];

        if(!ok[y])
        {
            ok[y] = 1;
            dfs(y);
        }
    }
    niv--;
}

void bfs(int x)
{
    for(int i = 1; i <= n; i++)
        ok[i] = 0;

    d[x] = 1;
    ok[x] = 1;
    q.push(x);

    while(!q.empty())
    {
        x = q.front();
        q.pop();

        for(size_t i = 0; i < a[x].size(); i++)
        {
            int y = a[x][i];

            if(!ok[y])
            {
                d[y] = d[x] + 1;
                if(d[y] > dmax)
                    dmax = d[y];
                ok[y] = 1;
                q.push(y);
            }
        }
    }
}


void citire()
{
    in >> n;

    for(int i = 1; i <= n - 1; i++)
    {
        int x, y;
        in >> x >> y;

        a[x].push_back(y);
        a[y].push_back(x);
    }
}

int main()
{
    citire();
    dfs(1);
    bfs(xmax);

    out << dmax << '\n';
    return 0;
}