//yuki778.cpp
//Mon Jan 13 11:11:32 2020

#include <iostream>
#include <string>
#include <queue>
#include <map>
#include <unordered_map>
#include <vector>
#include <algorithm>
#include <math.h>
#include <set>
#define INTINF 2147483647
#define LLINF 9223372036854775807
using namespace std;
using ll=long long;
typedef pair<int,int> P;

vector<int> graph[200010];
vector<int> tour;
int l[200010];
int r[200010];
int bit[500010];

void add(int x, int y){
	while(x<=tour.size()+1){
		bit[x] += y;
		x += x & -x;
	}
}

int sum(int i){
	int ans = 0;
	while (i>0){
		ans += bit[i];
		i -= i & -i;
	}
	return ans;
}

void dfs(int x){
	tour.push_back(x);
	if (l[x]==-1){
		l[x]=tour.size()-1;
	}else{
		r[x]=tour.size()-1;
	}
	for (int i=0;i<graph[x].size();i++){
		dfs(graph[x][i]);
		tour.push_back(x);
		r[x]=tour.size()-1;
	}
}

int main(){
	int n;
	cin >> n;

	for (int i=1;i<n;i++){
		int temp;
		cin >> temp;
		graph[temp].push_back(i);
	}

	fill(l,l+200010,-1);
	fill(r,r+200010,-1);
	dfs(0);

	fill(bit,bit+tour.size()+1,0);

	int ans = 0;
	for (int i=n-1;i>=0;i--){
		if (r[i]!=-1){
			ans += sum(r[i]+1)-sum(l[i]);
		}
		add(l[i]+1,1);
	}

//	for (int i=0;i<tour.size();i++){
//		cout << tour[i] << " ";
//	}
//	printf("\n");
//	for (int i=0;i<n;i++){
//		cout << i << " " << l[i] << " " << r[i] << endl;
//	}

	cout << ans << endl;
}