#include <bits/stdc++.h>
#define LL long long
#define PII pair<int,int>
using namespace std;
const int MAXN = 1005;
const int MAXX = 5005;
const int INF = (LL)1e9 + 5;

int X[MAXN], minv[MAXN], dp[MAXX], N;
vector<int> ch[MAXN];

void nope() {
	cout << "IMPOSSIBLE\n";
	exit(EXIT_SUCCESS);
}

void dfs(int v) {
	if (ch[v].empty()) {
		minv[v] = 0;
		return;
	}
	
	for (int to : ch[v]) {
		dfs(to);
	}
	
	fill(dp, dp + 5001, INF);
	dp[0] = 0;
	
	for (int to : ch[v]) {
		int c1 = X[to], c2 = minv[to];
		for (int j = 5000; j >= 0; j--) {
			int a = INF, b = INF;
			if (j >= c1) a = dp[j - c1] + c2;
			if (j >= c2) b = dp[j - c2] + c1;
			dp[j] = min(a, b);
		}
	}
	
	minv[v] = *min_element(dp, dp + X[v] + 1);
	if (minv[v] == INF) {
//		cout << v << " NO!!\n";
		nope();
	}
}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> N;
	for (int i = 2; i <= N; i++) {
		int p;
		cin >> p;
		ch[p].push_back(i);
	}
	
	for (int i = 1; i <= N; i++) cin >> X[i];
	
	dfs(1);
	cout << "POSSIBLE\n";
	
	return 0;
	
	/**** Note MAXN ****/
}
