#include <bits/stdc++.h>
using namespace std;
const int maxn = 1234;
int x[maxn], f[maxn];
vector<int> to[maxn];
void cant(){
	cout << "IMPOSSIBLE" << endl;
	exit(0);
}
void calc(int u){
	if(to[u].size()){
		vector<int> cf(x[u] + 1, 1<<30);
		cf[0] = 0;
		for(int v : to[u]){
			calc(v);
			vector<int> nf(x[u] + 1, 1<<30);
			for(int i = 0; i <= x[u]; i++){
				if(cf[i] != (1<<30)){
					if(i + x[v] <= x[u]) nf[i + x[v]] = min(nf[i + x[v]], cf[i] + f[v]);
					if(i + f[v] <= x[u]) nf[i + f[v]] = min(nf[i + f[v]], cf[i] + x[v]);
				}
			}
			cf = nf;
		}
		f[u] = 1<<30;
		for(int i = 0; i <= x[u]; i++) f[u] = min(f[u], cf[i]);
		if(f[u] == (1<<30)) cant();
	} else {
		f[u] = 0;
	}
}
int main(){
	int n; cin >> n;
	for(int i = 2; i <= n; i++){
		int x; cin >> x;
		to[x].push_back(i);
	}
	for(int i = 1; i <= n; i++) cin >> x[i];
	calc(1);
	cout << "POSSIBLE" << endl;
	return 0;
}

