#include<bits/stdc++.h>
#define inf 1000000000
#define N 1009
#define M 5009
using namespace std;

int n,a[N],f[N],fa[N],fst[N],nxt[N],dp[N][M],g[M];
void dfs(int x){
	int i,y;
	memset(dp[x],60,sizeof(dp[x])); dp[x][0]=0;
	for (y=fst[x]; y; y=nxt[y]){
		dfs(y);
		memset(g,60,sizeof(g));
		for (i=5000; i>=0; i--){
			if (i>=a[y]) g[i]=dp[x][i-a[y]]+f[y];
			if (i>=f[y]) g[i]=min(g[i],dp[x][i-f[y]]+a[y]);
		}
		memcpy(dp[x],g,sizeof(g));
	}
	f[x]=inf;
	for (i=a[x]; i>=0; i--) f[x]=min(f[x],dp[x][i]);
	if (f[x]==inf){ puts("IMPOSSIBLE"); exit(0); }
}
int main(){
	scanf("%d",&n);
	int i;
	for (i=2; i<=n; i++){
		scanf("%d",&fa[i]);
		nxt[i]=fst[fa[i]]; fst[fa[i]]=i;
	}
	for (i=1; i<=n; i++) scanf("%d",&a[i]);
	dfs(1);
	puts("POSSIBLE");
	return 0;
}
