#include <bits/stdc++.h>
using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");
vector < int > v[100005];
bool viz[100005];
int n, maxim = -1 << 30,start, cost[100005];
void read()
{
     in >> n;
     int a,b;
     for(int i=1; i<n; i++)
     {
          in >> a >> b;
          v[a].push_back(b);
          v[b].push_back(a);
     }
}
void dfs(int nod)
{
     viz[nod] = 1;
     for(int i=0; i<v[nod].size(); i++)
          if( !viz[v[nod][i]] )
          {
               cost[v [nod][i] ] = cost[nod] +1;
                if( cost[ v[nod][i]] > maxim )
                {
                     maxim = cost[ v[nod][i] ];
                     start = v[nod][i];
                }
               dfs( v[nod][i] );
          }
}
int main()
{
     read();
     dfs(1);
     memset( viz, 0, sizeof viz);
     memset( cost, 0, sizeof cost);
     dfs(start);
     out << maxim+1;

    return 0;
}