using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Globalization;
//using System.Diagnostics;
using static System.Console;
using Pair = System.Collections.Generic.KeyValuePair<int, int>;
//using System.Numerics;
//using static System.Math;
using static System.Linq.Enumerable;

class Program
{
    static void Main()
    {
        //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().solve();
        Out.Flush();
    }
    Scanner cin = new Scanner();
    Random rnd = new Random();
    System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
    readonly int[] dd = { 0, 1, 0, -1, 0 };
    readonly int mod = 1000000007;
    readonly string alfa = "abcdefghijklmnopqrstuvwxyz";
    readonly string ALFA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    int N;
    int[] P;
    int[] X;
    bool ans = true;
    List<int>[] G;
    void solve()
    {
        N = cin.nextint;
        if (N == 1)
        {
            ReadLine();
            ReadLine();
            WriteLine("POSSIBLE");
            return;
        }
        P = cin.scanint.Select(i => i - 1).ToArray();
        G = Range(0, N).Select(i => new List<int>()).ToArray();
        for (int i = 0; i < P.Length; i++)
        {
            G[P[i]].Add(i + 1);
        }
        X = cin.scanint;
        calc(0);

        WriteLine(ans ? "POSSIBLE" : "IMPOSSIBLE");
    }

    int calc(int u)
    {
        if (!ans)
        {
            return 0;
        }
        if (G[u].Count == 0)
        {
            return 0;
        }
        int small = 0, big = 0;
        foreach (var v in G[u])
        {
            int x = calc(v);
            small += Math.Min(X[v], x);
            big += Math.Max(X[v], x);
        }

        if (small > X[u])
        {
            ans = false;
            return 0;
        }

        if (big <= X[u])
        {
            return small;
        }
        else
        {
            return big;
        }
    }

}

class Scanner
{
    string[] s; int i;
    char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] scan { get { return ReadLine().Split(); } }
    public int[] scanint { get { return Array.ConvertAll(scan, int.Parse); } }
    public long[] scanlong { get { return Array.ConvertAll(scan, long.Parse); } }
    public double[] scandouble { get { return Array.ConvertAll(scan, double.Parse); } }
    public string next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return next;
        }
    }
    public int nextint { get { return int.Parse(next); } }
    public long nextlong { get { return long.Parse(next); } }
    public double nextdouble { get { return double.Parse(next); } }
}