#include<stdio.h>
#include<vector>
#include<algorithm>
using namespace std;
int dp[2][5555];
vector<int>ko[1111];
int mok[1111];
int dfs(int node)
{
	vector<int>v;
	for (int i = 0; i < ko[node].size(); i++)v.push_back(dfs(ko[node][i]));
	int cur = 0;
	for (int i = 0; i <= mok[node]; i++)dp[0][i] = 0, dp[1][i] = 1000000000;
	for (int i = 0; i < ko[node].size(); i++)
	{
		int z = v[i], y = mok[ko[node][i]];
		for (int j = 0; j <= mok[node]; j++)
		{
			if (j + y <= mok[node])dp[1 - cur][j + y] = min(dp[1 - cur][j + y], dp[cur][j] + z);
			if (j + z <= mok[node])dp[1 - cur][j + z] = min(dp[1 - cur][j + z], dp[cur][j] + y);
		}
		for (int j = 0; j <= mok[node]; j++)dp[cur][j] = 1000000000;
		cur = 1 - cur;
	}
	return dp[cur][mok[node]];
}
int main()
{
	int num;
	scanf("%d", &num);
	for (int i = 1; i < num; i++)
	{
		int z;
		scanf("%d", &z);
		z--;
		ko[z].push_back(i);
	}
	for (int i = 0; i < num; i++)scanf("%d", &mok[i]);
	if (dfs(0) >= 1000000000)printf("IMPOSSIBLE\n");
	else printf("POSSIBLE\n");
}