/*
    Keep It Simple!
*/

#include<stdio.h>
#include<list>
#include<string.h>

using namespace std;

#define Max(a,b) (a>b?a:b)

int n,dist[100005],Vmax,pos;
list<int> G[100005];

void DFS(int node)
{
   for(list<int>::iterator it = G[node].begin(); it!=G[node].end(); it++)
     if(!dist[*it])
     {
        dist[*it] = dist[node]+1;
        if(dist[*it]>Vmax)
        {
           Vmax = dist[*it];
           pos = *it;
        }
        DFS(*it);
     }
}

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

   scanf("%d",&n);
   int x,y;
   for(int i=1;i<=n;i++)
   {
     scanf("%d%d",&x,&y);
     G[x].push_back(y);
     G[y].push_back(x);
   }

   DFS(1);
   memset(dist,0,(n+2)*4);
   Vmax = 0;
   DFS(pos);
   printf("%d",Vmax+1);
}