#include <stdio.h>
#include <vector>

const int MAX_N = 100000;
std::vector<int> G[1 + MAX_N];
bool visited[1 + MAX_N];

int node, max;

void dfs(int u, int dist) {
  visited[u] = true;
  if (dist > max) {
    max = dist;
    node = u;
  }
  for (int v : G[u])
    if (!visited[v])
      dfs(v, dist + 1);
}

int main() {

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

  int n;
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    G[u].push_back(v);
    G[v].push_back(u);
  }
  dfs(1, 1);
  for (int i = 1; i <= n; i++)
    visited[i] = false;
  dfs(node, 1);
  printf("%d\n", max);

  fclose(stdin);
  fclose(stdout);

  return 0;
}