#include <cstdio>
#include <vector>
#include <queue>
#include <cstring>
#define inf 0x3f3f3f3f
#define nmax 100005

using namespace std;

int d[nmax],mxm,pozmxm,n;
vector<int> g[nmax];
queue<int> q;

void citire()
{
    int x,y;
    scanf("%d",&n);
    for(int i=1;i<=n-1;i++)
    {
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    memset(d,inf,sizeof(d));
}

void bfs(int nod)
{
    int k;
    d[nod]=0;
    q.push(nod);
    mxm=-1;
    while(!q.empty())
    {
        k=q.front();
        q.pop();
        if(d[k]>mxm)
        {
            mxm=d[k];
            pozmxm=k;
        }
        for(vector<int>::iterator ii=g[k].begin();ii!=g[k].end();++ii)
            if(d[*ii]==inf)
            {
                d[*ii]=d[k]+1;
                q.push(*ii);
            }
    }
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    citire();
    bfs(1);
    memset(d,inf,sizeof(d));
    bfs(pozmxm);
    printf("%d\n",mxm+1);
    return 0;
}