#include <bits/stdc++.h>

using namespace std;

const int nmax = 1e5 + 10;

int n;
vector < int > g[nmax];

void input() {
    scanf("%d", &n);
    for (int i = 1; i < n; ++i) {
        int x, y;
        scanf("%d %d", &x, &y);

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

void dfs(int node, int dad, int lvl, int &X, int &lvlX) {
    if (lvl > lvlX)
        lvlX = lvl, X = node;
    for (auto &it: g[node]) {
        if (it == dad) continue;
        dfs(it, node, lvl + 1, X, lvlX);
    }
}

int compute_D() {
    int X, lvlX = 0, Y, lvlY = 0;
    dfs(1, 0, 1, X, lvlX);
    dfs(X, 0, 1, Y, lvlY);
    return lvlY;
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);

    input();
    printf("%d\n", compute_D());

    return 0;
}