package main

import (
	"bufio"
	"fmt"
	"math"
	"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++ {
		p := getNextInt(scanner) - 1
		g.appendEdge(p, i, i)
	}
	for i := 0; i < n; i++ {
		g.v[i].x = getNextInt(scanner)
		g.v[i].dp = math.MaxInt32
	}
	g.dfs(0)
	for i := 0; i < n; i++ {
		if g.v[i].dp == math.MaxInt32 {
			fmt.Fprintln(writer, "IMPOSSIBLE")
			return
		}
	}
	fmt.Fprintln(writer, "POSSIBLE")
}

type vertex struct {
	x, dp 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(c int) {
	var sum int
	if len(g.e[c]) == 0 {
		g.v[c].dp = 0
		return
	}
	dp := make([]int, 5005)
	dp[0] = 1
	mn := 5005
	for _, e := range g.e[c] {
		g.dfs(e.to)
		sum += g.v[e.to].x + g.v[e.to].dp
		for i := 5000; i >= 0; i-- {
			if mn > g.v[e.to].x {
				mn = g.v[e.to].x
			}
			if mn > g.v[e.to].dp {
				mn = g.v[e.to].dp
			}
			if i-g.v[e.to].x >= 0 {
				dp[i] = dp[i] | dp[i-g.v[e.to].x]
			}
			if i-g.v[e.to].dp >= 0 {
				dp[i] = dp[i] | dp[i-g.v[e.to].dp]
			}
		}
	}
	for i := g.v[c].x; i >= mn; i-- {
		if dp[i] == 1 {
			g.v[c].dp = sum - i
			break
		}
	}
}
