#include <cstdio>
#include <vector>
#include <deque>
using namespace std;
int n,u[100007],k,kp;

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    int i,x,y;
    vector <int> v[100007];
    deque <int> q;
    scanf("%d",&n);
    for(i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    q.push_back(1);
    u[1]=-1;
    while(!q.empty())
    {
        for(i=0;i<v[q.front()].size();i++)
        {
            if(!u[v[q.front()][i]])
            {
                u[v[q.front()][i]]=u[q.front()]-1;
                if(k>u[v[q.front()][i]])
                {
                    k=u[v[q.front()][i]];
                    kp=v[q.front()][i];
                }
            }
        }
    }
    q.push_back(kp);
    u[kp]=1;
    k=0;
    while(!q.empty())
    {
        for(i=0;i<v[q.front()].size();i++)
        {
            if(u[v[q.front()][i]]<0)
            {
                u[v[q.front()][i]]=u[q.front()]+1;
                if(k<u[v[q.front()][i]])
                {
                    k=u[v[q.front()][i]];
                    kp=v[q.front()][i];
                }
            }
        }
    }
    printf("%d\n",k);
    return 0;
}