#include <vector>
#include <cstdio>
#include <queue>
#include <cstring>
using namespace std;

const int maxn=100005;

vector <int > g[maxn];
queue < pair < int ,int  > > q;

int last,n,viz[maxn],drum=1;

void citire ()
{
    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);
    }
}

void bfs(int incep)
{
    q.push(make_pair(incep,1));
    viz[incep]=1;
    memset(viz,0,maxn);
    while (!q.empty())
    {
        int nod=q.front().first;
        int d=q.front().second;
        q.pop();

        for (vector < int > ::iterator it=g[nod].begin();it!=g[nod].end();++it)
            if (!viz[*it])
            {
                viz[*it]=1;
                q.push(make_pair(*it,d+1));

                last=*it;
                drum=d+1;
            }
    }
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    citire();
    bfs(1);
    bfs(last);
    printf("%d",drum);
    return 0;
}