import java.util.Scanner;

class Main{

public static void main(String[] args) {

Scanner in= new Scanner(System.in);

while(in.hasNext()){

int n = in.nextInt();

int[] tree = new int[n];

for (int i = 0; i < tree.length; i++) {

tree[i]=-1;

}

for(int i =0;i<n-1;i++){

int p = in.nextInt();

int c = in.nextInt();

tree[c] =p;

}

int max=1;

int count =0;

for (int i = n-1; i >0; --i) {

int cur=i;

while(cur!=-1)

{

cur = tree[cur];

count++;

}

if(count>max) max =count;

count=0;

}

System.out.println(max);

}

}

}

//O（n）解   你思路是对的