#include <bits/stdc++.h>
#define endl '\n'

using namespace std;
const int MAXN = (5042);

int n;
int a[MAXN];
vector<int> adj[MAXN];

void read()
{
	cin >> n;
	for(int i = 2; i <= n; i++) 
	{
		int p;
		cin >> p;
		adj[p].push_back(i);
	}
	
	for(int i = 1; i <= n; i++) cin >> a[i];
}

int sum[MAXN][2];

void dfs(int u)
{
	if(adj[u].size() == 0)
	{
		sum[u][0] = a[u];
		sum[u][1] = 0;
		return;	
	}

	bitset<MAXN> bs; bs[0] = 1;
	int sum_all = 0;
	
	for(int v: adj[u])
	{
		dfs(v);
		bs = (bs << sum[v][0]) | (bs << sum[v][1]);
		sum_all += sum[v][0] + sum[v][1];
	}
	
	int val = -1;
	for(int i = 0; i <= a[u]; i++)
		if(bs[i]) val = i;

	if(val == -1)
	{
		cout << "IMPOSSIBLE" << endl;
		exit(0);
	}

	sum[u][0] = a[u];
	sum[u][1] = sum_all - val;
}

void solve()
{
	dfs(1);
	cout << "POSSIBLE" << endl;
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	read();
	solve();
	return 0;
}

