#include<cstdio>
typedef unsigned long long ull;
struct Edge{int to;Edge*next;}E[1010],*fir[1010];
int n,a[1010],b[1010];
ull f[80];
bool dfs(int i){
	int lim=a[i],sum=0,m=0;
	for(Edge*e=fir[i];e;e=e->next){
		if(!dfs(e->to))return 0;
		lim-=a[e->to];
		sum+=b[e->to];
	}
	if(lim<0)return 0;
	for(;m<<6<=lim;m++)f[m]=!m;
	for(Edge*e=fir[i];e;e=e->next){
		int u=b[e->to]-a[e->to],v=u&63;
		u>>=6;
		for(int j=m;j-->u;){
			f[j]|=f[j-u]<<v;
			if(j>u&&v)f[j]|=f[j-u-1]>>64-v;
		}
	}
	for(int j=m;j--;){
		int v=lim+1-(j<<6);
		if(v<64)f[j]&=(1ull<<v)-1;
		if(f[j]){
			v=j<<6|63-__builtin_clzll(f[j]);
			v=sum-v;
			if(v<a[i])b[i]=a[i],a[i]=v;
			else b[i]=v;
			return 1;
		}
	}
}
int main(){
	scanf("%d",&n);
	for(int i=2,p;i<=n;i++)scanf("%d",&p),E[i]=(Edge){i,fir[p]},fir[p]=E+i;
	for(int i=1;i<=n;i++)scanf("%d",a+i);
	puts(dfs(1)?"POSSIBLE":"IMPOSSIBLE");
}