#include <fstream>
#include <vector>

using namespace std;

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

const int nmax = 100005;
bool viz[nmax];
vector<int> ls[nmax];
int n, x, y, i, niv[nmax], maxim, pmax;

void dfs(int x) {
    int l = ls[x].size(), i, y;
    viz[x] = 1;
    for (i = 0; i < l; i++) {
        y = ls[x][i];
        if (viz[y]) continue;
        niv[y] = niv[x]+1;
        dfs(y);
    }

}

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

    dfs(1);
    for (i = 1; i <= n; i++)
        if (niv[i] > maxim)
            maxim = niv[i], pmax = i;

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

    niv[pmax] = 1;
    dfs(pmax);
    maxim = 0;
    for (i = 1; i <= n; i++)
        if (niv[i] > maxim)
            maxim = niv[i], pmax = i;

    g << maxim;

    return 0;
}