#include <iostream>
#include <vector>
#include <list>

using namespace std;


struct Node {
	Node(){
		count=0;
	}
	int i;
	int parent;
	vector<int> children;
	int count;
};

void count(vector<Node> &nodes,Node &node,list<Node*> path)
{
	for(int i=0;i<node.children.size();i++){
		int c = node.children[i];
		Node &child = nodes[c];
		path.push_back(&node);
		count(nodes,child,path);
		path.pop_back();
	}
	for( auto &x: path){
		if(x->i<node.i){
			node.count++;
		}
	}
}

int main() {
	
	int N;
	cin >> N;
	vector<Node> nodes(N);

	nodes[0].i=0;
	nodes[0].parent=-1;

	for(int i=1;i<nodes.size();i++){
		int parent;
		cin >> parent;
		nodes[i].i = i;
		nodes[i].parent = parent;
		nodes[parent].children.push_back(i);
	}

	list<Node*> path;
	count(nodes,nodes[0],path);
	int ans = 0;
	for(int i=0;i<nodes.size();i++){
		ans += nodes[i].count;
	}
	cout << ans;

	// your code goes here
	return 0;
}