#include <bits/stdc++.h>
using namespace std;
const int maxn = 1000 + 10;
const int maxb = 5000 + 10;
const int INF = maxn * maxb + 10;
int n, a[maxn], f[maxn][2], dp[maxn][maxb];
vector<int> E[maxn];
void dfs(int x)
{
	for(auto v : E[x])
		dfs(v);
	for(int k = 0; k < 2; ++k)
	{
		for(int i = 0; i <= E[x].size(); ++i)
			fill(dp[i], dp[i] + a[x] + 1, INF);
		dp[0][0] = 0;
		for(int i = 1; i <= E[x].size(); ++i)
		{
			int v = E[x][i - 1];
			for(int j = 0; j <= a[x]; ++j)
			{
				if(j >= a[v]) dp[i][j] = min(dp[i][j], dp[i - 1][j - a[v]] + f[v][k ^ 1]);
				if(j >= f[v][k]) dp[i][j] = min(dp[i][j], dp[i - 1][j - f[v][k]] + a[v]);
			}
		}
		f[x][k] = INF;
		for(int j = 0; j <= a[x]; ++j) f[x][k] = min(f[x][k], dp[E[x].size()][j]);
	}
}
int main()
{
	scanf("%d", &n);
	for(int i = 2; i <= n; ++i) 
	{
		int v;
		scanf("%d", &v); 
		E[v].push_back(i);
	}
	for(int i = 1; i <= n; ++i) scanf("%d", &a[i]);
	dfs(1);
	if(min(f[1][0], f[1][1]) < INF) puts("POSSIBLE");
	else puts("IMPOSSIBLE");
	return 0;
}
	