#include<cstdio>
#include<vector>
#include<cstring>
#define NMAX 100005
using namespace std;
vector<int>v[NMAX];
int tata[NMAX],d[NMAX],viz[NMAX],viz1[NMAX],q[NMAX];
int n,m,i,poz,last,x,y,Max;
void BFS1(int nod)
{
    viz[nod]=1;
    int st=1,dr=1;
    q[st]=nod;
    while(st<=dr)
    {
        int x=q[st];++st;
        last=x;
        vector<int>::iterator it;
        for (it=v[x].begin();it!=v[x].end();++it)
        {
            if (viz[*it]==0)
            {
                q[++dr]=*it;
                viz[*it]=1;
            }
        }
    }
}
void BFS2(int nod)
{
    int st=1,dr=1;
    q[st]=last;
    viz1[nod]=1;
    while(st<=dr)
    {
        int x=q[st];++st;
        if (d[x]>Max) Max=d[x],poz=x;
        vector<int>::iterator it;
        for (it=v[x].begin();it!=v[x].end();++it)
        {
            if (viz1[*it]==0)
            {
                q[++dr]=*it;
                d[*it]=d[x]+1;
                tata[*it]=x;
                viz1[*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);
    d[last]=0;
    BFS2(last);
    printf("%d\n",Max);
    /*while(tata[poz]!=0)
    {
        printf("%d ",poz);
        poz=tata[poz];
    }
    printf("%d\n",poz);*/
    return 0;
}