#include<cstdio>
#include<vector>
#include<queue>
#include<cstring>
#define NMAX 100005
using namespace std;
vector<int>v[NMAX];
queue<int>q;
int tata[NMAX],d[NMAX],viz[NMAX];
int n,m,i,poz,last,x,y;
void BFS1(int nod)
{
    q.push(nod);
    viz[nod]=1;
    while(!q.empty())
    {
        int x=q.front();
        q.pop();
        last=x;
        vector<int>::iterator it;
        for (it=v[x].begin();it!=v[x].end();++it)
        {
            if (viz[*it]==0)
            {
                q.push(*it);
                viz[*it]=1;
            }
        }
    }
}
void BFS2(int nod)
{
    q.push(nod);
    viz[nod]=1;
    while(!q.empty())
    {
        int x=q.front();
        q.pop();
        last=x;
        vector<int>::iterator it;
        for (it=v[x].begin();it!=v[x].end();++it)
        {
            if (viz[*it]==0)
            {
                q.push(*it);
                d[*it]=d[x]+1;
                tata[*it]=nod;
                viz[*it]=1;
            }
        }
    }
}

int main()
{
    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);
            v[x].push_back(y);
            v[y].push_back(x);
        }
    BFS1(1);
    memset(viz,0,sizeof(viz));
    d[last]=1;
    BFS2(last);
    int Max=0;
    for (i=1;i<=n;++i)
        if (d[i]>Max) {Max=d[i];poz=i;}
    printf("%d\n",Max);
   /* while(tata[poz]!=0)
    {
        printf("%d ",poz);
        poz=tata[poz];
    }
    printf("%d\n",poz);*/
    return 0;
}