#include <bits/stdc++.h>

using namespace std;

const int nmax = 1e5 + 10;

int n, len, node2;
vector < int > g[nmax];

void dfs(int node, int dad, int lvl) {
    if (lvl > len) len = lvl, node2 = node;

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

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

    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);
    }

    len = 0; dfs(1, 0, 1);
    len = 0; dfs(node2, 0, 1);

    printf("%d\n", len);

    return 0;
}