#include <bits/stdc++.h>

using namespace std;

ifstream fin ("darb.in");
ofstream fout ("darb.out");

 #define NMAX 100005

vector<int>v[NMAX];
int n, x, y, d[NMAX], viz[NMAX], maxx, p;

void dfs(int x)
{
viz[x] = 1;
for (int i = 0; i < v[x].size(); i++)
{
int vecin = v[x][i];
if (!viz[vecin])
{
d[vecin] = d[x] + 1;
if (maxx < d[vecin])
{
p = vecin;
maxx = d[vecin];
}
dfs(vecin);
}
}
}

int main()
{
  fin >> n;
  for (int i = 1; i < n; i++)
  {
    fin >> x >> y;
    v[x].push_back(y);
    v[y].push_back(x);
  }
  d[1] = 1;
  dfs(1);
  memset(viz, 0, sizeof(viz));
  memset(d, 0, sizeof(d));
  d[p] = 1;
  dfs(p);
  maxx = 0;
  for (int i = 1; i <= n; i++)
  {
    if (maxx < d[i])
      maxx = d[i];
  }
  fout << maxx;
  return 0;
}