package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	n := getNextInt(scanner)
	g := newGraph(n)
	for i := 1; i < n; i++ {
		a := getNextInt(scanner)
		g.appendEdge(a, i, i-1)
	}
	var c int
	c = -1
	g.dfs(0, -1, func() int { c++; return c })
	seg := newSegment(n << 1)
	var ans int
	for i := n - 1; i >= 0; i-- {
		ans += seg.query(g.v[i].l, g.v[i].r+1, 0, seg.add)
		seg.update(g.v[i].l, 1, seg.add)
	}
	fmt.Fprintln(writer, ans)
}

type vertex struct {
	l, r, c int
}
type edge struct {
	to, id int
}
type graph struct {
	v []vertex
	e [][]edge
}

func newGraph(n int) graph {
	return graph{
		v: make([]vertex, n),
		e: make([][]edge, n),
	}
}
func (g *graph) appendEdge(from, to, id int) {
	g.e[from] = append(g.e[from], edge{
		to: to,
		id: id,
	})
}
func (g *graph) dfs(i, p int, fn func() int) {
	g.v[i].l = fn()
	for _, e := range g.e[i] {
		if e.to == p {
			continue
		}
		g.dfs(e.to, i, fn)
	}
	g.v[i].r = fn()
}

type segment [][]int

func newSegment(n int) segment {
	seg := make(segment, 0)
	for n > 1 {
		seg = append(seg, make([]int, n))
		n = (n + 1) >> 1
	}
	seg = append(seg, make([]int, 1))
	return seg
}
func (seg segment) update(i int, v int, f func(int, int) int) {
	seg[0][i] = v
	for h := 1; h < len(seg); h++ {
		i >>= 1
		if i<<1+1 < len(seg[h-1]) {
			seg[h][i] = f(seg[h-1][i<<1], seg[h-1][i<<1+1])
		} else {
			seg[h][i] = seg[h-1][i<<1]
		}
	}
}
func (seg segment) query(l, r int, s int, f func(int, int) int) int {
	for h := 0; h < len(seg) && l < r; h++ {
		if l&1 == 1 {
			s = f(s, seg[h][l])
			l++
		}
		l >>= 1
		if r&1 == 1 {
			s = f(s, seg[h][r-1])
		}
		r >>= 1
	}
	return s
}
func (seg segment) add(x, y int) int {
	return x + y
}