#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <bitset>
#include <cstring>
#define nmax 100006
using namespace std;

int n,maxd,nod;
int d[nmax];
vector<int> m[nmax];
bitset<nmax> viz;
queue<int> q;

inline int bfs(int nod)
{
    int poz,sol;
    maxd=-3;
    viz.reset();
    memset(d,0,sizeof(d));
    q.push(nod);
    while(!q.empty())
    {
        poz=q.front(); q.pop();
        for(vector<int>::iterator it=m[poz].begin();it!=m[poz].end();it++)
            if(!viz[*it])
            {
                viz[*it]=1;
                d[*it]=d[poz]+1;
                if(d[*it]>maxd) { maxd=d[*it]; sol=*it; }
                q.push(*it);
            }
    }
    return sol;
}

int main()
{
    int i,n1,n2;
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<n;i++)
    {
        scanf("%d%d",&n1,&n2);
        m[n1].push_back(n2);
        m[n2].push_back(n1);
    }
    cout<<d[ bfs( bfs(1) ) ]+1<<'\n';;
    fclose(stdin);
    fclose(stdout);
    return 0;
}