import std.algorithm;
import std.array;
import std.ascii;
import std.bigint;
import std.complex;
import std.container;
import std.conv;
import std.functional;
import std.math;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

auto readInts() {
	return array(map!(to!int)(readln().strip().split()));
}
auto readInt() {
	return readInts()[0];
}
auto readLongs() {
	return array(map!(to!long)(readln().strip().split()));
}
auto readLong() {
	return readLongs()[0];
}

void readlnTo(T...)(ref T t) {
    auto s = readln().split();
    assert(s.length == t.length);
    foreach(ref ti; t) {
        ti = s[0].to!(typeof(ti));
        s = s[1..$];
    }
}

const real eps = 1e-10;

const long p = 1_000_000_000 + 7;

class Tree {
    this(int i) {
        this.i = i;
        this.h = -1;
    }
    int i;
    long h;
    Tree[] c;

    void calcHeight() { 
        if(h >= 0) {
            return;
        }
        if(c.empty()) {
            h = 0;
        } else {
            long[] hs;
            foreach(ci; c) {
                ci.calcHeight();
                hs ~= ci.h;
            }
            hs.sort();
            h = reduce!(max)(0L, hs.zip(iota(hs.length).retro()).map!(a => a[0] + a[1]).array) + 1;
        }
    }
}

void main(){
    auto n = readInt();
    int[] a;
    foreach(i; iota(n-1)) {
        a ~= readInt()-1;
    }
    auto t = new Tree[](n);
    foreach(i; iota(n)) {
        t[i] = new Tree(i);
    }
    foreach(i, k; a) { 
        int j = i+1;
        t[k].c ~= t[j];
    }
    t[0].calcHeight();
    writeln(t[0].h);
}

