#include <cstring>
#include <fstream>
#include <vector>
using namespace std;

const int MAX = 100005;

vector<int> G[MAX];
int N, diameter, lastNode;
bool viz[MAX];

void dfs(int node, int level) {
    if (level + 1 > diameter)
        diameter = level + 1, lastNode = node;
    viz[node] = 1;
    for (auto &elem: G[node])
        if (viz[elem] == 0)
            dfs(elem, level + 1);
}

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

    f >> N;
    for (int i = 1, x, y; i < N; ++i) {
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    dfs(1, 0);
    memset(viz, 0, sizeof(viz));
    dfs(lastNode, 0);

    g << diameter;
}