using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
static class Program{
	const int mod=(int)1e9+7;
	static List<int>[] li;
	static int[][] dp;
	static int[] x;
	static int o=10000;
	static void Main(){
		Sc sc=new Sc();
		var n=sc.I;
		if(n==1){Console.WriteLine("POSSIBLE");return;}
		var p=sc.Ia;
		x=sc.Ia3(0);
		li=new List<int>[n+1];
		dp=new int[n+1][];
		for(int i=1;i<=n;i++){li[i]=new List<int>();}
		for(int i = 0;i<p.Length;i++) {li[p[i]].Add(i+2);}
		Console.WriteLine("{0}",Fu(1)!=o?"POSSIBLE":"IMPOSSIBLE");
	}
	static int Fu(int a){
		dp[a]=Enumerable.Repeat(o,x[a]+1).ToArray();
		dp[a][0]=0;
		int b=o;
		for(int i=0;i<li[a].Count;i++){
			int q=Fu(li[a][i]);
			for(int j = x[a];j>=0;j--) {
				dp[a][j]=Min(j>=q?dp[a][j-q]+x[li[a][i]]:o,j>=x[li[a][i]]?dp[a][j-x[li[a][i]]]+q:o);
				if(i==li[a].Count-1&&b>dp[a][j]){
					b=dp[a][j];
				}
			}
		}
		return li[a].Count==0?0:b;
	}
}

public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),int.Parse);}
	public int[] Ia3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),long.Parse);}
	public long[] La3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),long.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}
