#include <iostream>
#include <cstdio>
#include <queue>
#include <vector>
#define Nmax 100005
using namespace std;
vector <int> G[Nmax];
vector <int> ::iterator it;
queue <int> C;
int n,maxi,c1,c2,dis;
void citire(int &n)
{
    int i,x,y;
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n-1;++i)
    {
       scanf("%d %d",&x,&y);
       G[x].push_back(y);
       G[y].push_back(x);
    }

}
void BFS(int nod,int &cap1,int &maxi)
{
    int i,x,dmin[Nmax];
    bool viz[Nmax];
    for(i=1;i<=n;++i) {viz[i]=0;dmin[i]=0;}
    viz[nod]=1;
    C.push(nod);
    maxi=0;dis=0;
    while(!C.empty())
    {
        x=C.front();C.pop();
        for(it=G[x].begin();it!=G[x].end();++it)
         if (!viz[*it])
         {
             C.push(*it);
             dmin[*it]=dmin[x]+1;
             if (dmin[*it]>maxi) {maxi=dmin[*it];cap1=*it;}
             viz[*it]=1;
         }
    }
}
int main()
{
    citire(n);
    BFS(1,c1,dis);
    BFS(c1,c2,dis);
    printf("%d",dis+1);
    return 0;
}