#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
typedef int in;
#define int long long
#define double long double
#define f first
#define s second
#define pb push_back
#define pp push
#define ceill(x,y) ((x/y)+(x%y!=0)*(x/abs(x)*y/abs(y)<0?0:1))
#define floorr(x,y) ((x/y)+(x%y!=0)*(x/abs(x)*y/abs(y)<0?-1:0))
#define YN(x) cout<<(x?"YES\n":"NO\n");
#define Yn(x) cout<<(x?"Yes\n":"No\n");
#define yn(x) cout<<(x?"yes\n":"no\n");
const int MAAX=1e18;
const int MOD=1e9+7;
const int MAX=1e9;

int n,dist[200010],depth[200010],b[200010][20];
vector<int> v[200010];
int dfs(int idx,int par,int d=1){
	dist[idx]=MAAX;
	depth[idx]=d;
	b[idx][0]=par;
	for(int i=1;i<20;i++)
		b[idx][i]=b[b[idx][i-1]][i-1];
	for(int i=0;i<v[idx].size();i++){
		if(v[idx][i]==par)
			continue;
		dist[idx]=min(dfs(v[idx][i],idx,d+1),dist[idx]);
	}
	if(v[idx].size()==0)
		dist[idx]=0;
	return dist[idx]+1;
}
int up(int idx,int x){
	if(x==0)
		return idx;
	return up(b[idx][__lg(x)],x-(1<<__lg(x)));
}
int lca(int x,int y){
	if(depth[x]<depth[y])
		swap(x,y);
	x=up(x,depth[x]-depth[y]);
	for(int i=19;i>=0;i--){
		if(b[x][i]!=b[y][i]){
			x=b[x][i];
			y=b[y][i];
		}
	}
	return b[x][0];
}
int fun(int idx,int tar){
	if(idx==tar)
		return 0;
	return fun(up(tar,depth[tar]-depth[idx]-dist[idx]),tar)+1;
}
bool comp(int x,int y){
	return depth[x]>=depth[y];
}

in main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int tc=1;
    // cin>>tc;
    while(tc--){
    	std::chrono::time_point<std::chrono::system_clock> start, end;
	    start = std::chrono::system_clock::now();
		cin>>n;
		for(int i=2;i<=n;i++){
			int x;
			cin>>x;
			v[x].pb(i);
		}
		dfs(1,0);
		vector<int> vec;
		for(int i=1;i<=n;i++){
			if(v[i].size())
				continue;
			vec.pb(i);
		}
		sort(vec.begin(),vec.end(),comp);
		int ans=0;
		for(int i=0;i<vec.size();i++){
			end = std::chrono::system_clock::now();
		    std::chrono::duration<double> elapsed_seconds = end - start;
			if(elapsed_seconds.count()>0.8)
				break;
			ans=max(ans,fun(1,vec[i]));
		}
		cout<<ans<<"\n";
    }
    return 0;
}