#include "bits/stdc++.h"
using namespace std;

long long N;
vector<long long> X;
vector<vector<long long> > V;

pair<long long, long long> DFS(long long P) {
	vector<pair<long long, long long> > VP;
	for (long long NP : V[P]) {
		pair<long long, long long> Q = DFS(NP);
		if (Q.first == -1 && Q.second == -1) return { -1, -1 };
		VP.push_back(Q);
	}
	long long COUNT = 0;
	bitset<5010> BS;
	BS[0] = 1;
	for (pair<long long, long long> Q : VP) {
		BS = (BS << Q.first) | (BS << Q.second);
		COUNT += Q.first + Q.second;
	}
	long long MAX = -1;
	for (int i = 0; i <= X[P]; i++) if (BS[i]) MAX = i;
	if (MAX == -1) return { -1, -1 };
	return { X[P], COUNT - MAX };
}

int main() {
	cin >> N;
	V.resize(N);
	X.resize(N);
	for (int i = 1; i < N; i++) {
		long long P;
		cin >> P;
		P--;
		V[P].push_back(i);
	}
	for (int i = 0; i < N; i++) cin >> X[i];
	pair<long long, long long> ANS = DFS(0);
	if (ANS.first == -1 && ANS.second == -1) cout << "IMPOSSIBLE" << endl;
	else cout << "POSSIBLE" << endl;
}