#define _USE_MATH_DEFINES
#include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <string>
#include <vector>
#include <utility>
#include <complex>
#include <set>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>
#include <deque>
#include <tuple>
#include <bitset>
#include <limits>
#include <algorithm>
#include <array>
#include <random>
#include <complex>
#include <regex>
using namespace std;
typedef long double ld;
typedef long long ll;
typedef vector<int> vint;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef complex<ld> compd;
#define quickIO()	{cin.tie(0);	cout.sync_with_stdio(false);}
#define reach(i,a)	for(auto i:a)
#define rep(i,n)	for(int i=0;i<((int)n);i++)
#define REP(i,n)	for(int i=0;i<=((int)n);i++)
#define srep(i,a,n)	for(int i=a;i<((int)n);i++)
#define SREP(i,a,n)	for(int i=a;i<=((int)n);i++)
#define rrep(i,n)	for(int i=n-1;i>=0;i--)
#define RREP(i,n)	for(int i=n;i>=0;i--)
#define all(a)	(a).begin(),(a).end()
#define mp(a,b)	make_pair(a,b)
#define mt	make_tuple
#define pb	push_back
template<typename T> istream& operator >> (istream& is, vector<T>& vec) {
	for (T& x : vec)	is >> x;
	return is;
}
template<typename T> ostream& operator << (ostream& os, vector<T>& vec) {
	os << "[";
	rep(i, vec.size())	os << (i ? ", " : "") << vec[i];
	os << "]";
	return os;
}
template<typename T> istream& operator >> (istream& is, pair<T, T>& p) {
	is >> p.first >> p.second;
	return is;
}
template<typename T> ostream& operator << (ostream& os, pair<T, T>& p) {
	os << "(" << p.first << ", " << p.second << ")";
	return os;
}
int bitcnt(ll x) {
	x = ((x & 0xAAAAAAAAAAAAAAAA) >> 1) + (x & 0x5555555555555555);
	x = ((x & 0xCCCCCCCCCCCCCCCC) >> 2) + (x & 0x3333333333333333);
	x = ((x & 0xF0F0F0F0F0F0F0F0) >> 4) + (x & 0x0F0F0F0F0F0F0F0F);
	x = ((x & 0xFF00FF00FF00FF00) >> 8) + (x & 0x00FF00FF00FF00FF);
	x = ((x & 0xFFFF0000FFFF0000) >> 16) + (x & 0x0000FFFF0000FFFF);
	x = ((x & 0xFFFFFFFF00000000) >> 32) + (x & 0x00000000FFFFFFFF);
	return x;
}
int bitcnt(int x) {
	x = ((x & 0xAAAAAAAA) >> 1) + (x & 0x55555555);
	x = ((x & 0xCCCCCCCC) >> 2) + (x & 0x33333333);
	x = ((x & 0xF0F0F0F0) >> 4) + (x & 0x0F0F0F0F);
	x = ((x & 0xFF00FF00) >> 8) + (x & 0x00FF00FF);
	x = ((x & 0xFFFF0000) >> 16) + (x & 0x0000FFFF);
	return x;
}
ll sqrtll(ll x) {
	ll left = 0, right = x;
	rep(i, 100) {
		ll mid = (left + right) >> 1;
		if (mid*mid <= x)	left = mid;
		else	right = mid;
	}
	return left;
}
ll gcd(ll a, ll b) {
	return b == 0 ? a : gcd(b, a%b);
}
#define debug(x)	printf("Case #%d: ", x)
#define DEBUG 0
const int inf = 1e9;
const ld infl = 1e100;
const ll mod = 998244353;
const ld eps = 1e-9;
const int dx[] = { 1,0,-1,0,0 };
const int dy[] = { 0,1,0,-1,0 };

// dp[i][0]: 頂点iを黒に塗ったときの、iを根とする部分木の白い頂点の重みの最小値
int dp[1010][2];
vint edge[1010];
vint p, x;

bool solve(int pos) {
	// それぞれの子について、子がiの時、
	// (黒, 白) = (x[i], dp[i][0]) or (dp[i][1], x[i])
	// が必須。
	// posを黒に塗るなら、子の黒がx[pos]を超えない範囲で白の最小値を求めたい->これもDP。
	// dpb[i]: 黒く塗った頂点の重さの合計がiの時の白の重みの最小値
	// 根っこの時は以降の処理が不要
	if (edge[pos].size() == 0) {
		dp[pos][0] = dp[pos][1] = 0;
		return true;
	}
	vint dpb(x[pos] + 1, inf), dpw(x[pos] + 1, inf);
	dpb[0] = dpw[0] = 0;
	// 更新用
	vint dpb2, dpw2;
	rep(i, edge[pos].size()) {
		int to = edge[pos][i];
		// 既に無理なので諦めよ？
		if (!solve(to)) return false;
		// テーブルの更新(多分無いけど念のためinfを最大値にしてoverflowを回避します)
		dpb2 = vint(x[pos] + 1, inf);
		dpw2 = vint(x[pos] + 1, inf);
		REP(j, x[pos]) {
			if (j + x[to] <= x[pos]) {
				dpb2[j + x[to]] = min(inf, min(dpb2[j + x[to]], dpb[j] + dp[to][0]));
				dpw2[j + x[to]] = min(inf, min(dpw2[j + x[to]], dpw[j] + dp[to][1]));
			}
			if (j + dp[to][0] <= x[pos]) {
				dpw2[j + dp[to][0]] = min(inf, min(dpw2[j + dp[to][0]], dpw[j] + x[to]));
			}
			if (j + dp[to][1] <= x[pos]) {
				dpb2[j + dp[to][1]] = min(inf, min(dpb2[j + dp[to][1]], dpb[j] + x[to]));
			}
		}
		dpw = dpw2;
		dpb = dpb2;
	}
	// dp[pos][0] = min(dpb)
	// dp[pos][1] = min(dpw)
	// 両方存在しなければreturn false(片方のみ存在はあり得ない)
	dp[pos][0] = *min_element(all(dpb));
	dp[pos][1] = *min_element(all(dpw));
	if (dp[pos][0] == inf && dp[pos][1] == inf) {
		return false;
	}
	return true;
}

int main() {
	int n;	cin >> n;
	p.resize(n - 1);	cin >> p;
	x.resize(n);	cin >> x;
	rep(i, n - 1) {
		edge[p[i] - 1].push_back(i + 1);
	}
	cout << (solve(0) ? "POSSIBLE" : "IMPOSSIBLE") << endl;
	return 0;
}

Measured memory_bytes: 13452