#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int n,viz[100001],c[100001],maxim,nod;
vector <int> a[100001];
void bfs(int x)
{
    int i,prim,ultim;
    viz[x]=1;
    prim=ultim=1;
    c[prim]=x;
    while(prim<=ultim)
    {
        x=c[prim++];
        for(i=0;i<a[x].size();i++)
        {
            if(viz[a[x][i]]==0)
            {
                ultim++;
                c[ultim]=a[x][i];
                viz[a[x][i]]=viz[x]+1;
                if(viz[a[x][i]]>maxim)
                {
                    maxim=viz[a[x][i]];
                    nod=a[x][i];
                }
            }
        }
    }
}
int main()
{
    int i,x,y;
    f>>n;
    for(i=1;i<=n-1;i++)
    {
        f>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    maxim=1;
    nod=1;
    bfs(1);
    for(i=1;i<=n;i++)
    {
        viz[i]=c[i]=0;
    }
    maxim=1;
    bfs(nod);
    g<<maxim;
    return 0;
}