//Copyright(c)2017 Mstdream
#include<bits/stdc++.h>
using namespace std;

inline void splay(int &v){
	v=0;char c=0;int p=1;
	while(c<'0' || c>'9'){if(c=='-')p=-1;c=getchar();}
	while(c>='0' && c<='9'){v=(v<<3)+(v<<1)+c-'0';c=getchar();}
	v*=p;
}
const int N=10010;
int nxt[N],fir[N],sz,to[N],dp[N],v[N],n;
bitset<5005>a[N],b[N];
void add(int x,int y){
	nxt[++sz]=fir[x],fir[x]=sz,to[sz]=y;
}
void dfs(int x){
	if(fir[x]){
		dp[x]=1<<30;
		int tot=0;a[x][0]=1;
		for(int u=fir[x];u;u=nxt[u]){
			dfs(to[u]);
			b[x]=a[x]<<v[to[u]];
			b[x]|=a[x]<<dp[to[u]];
			a[x]=b[x];
			tot+=v[to[u]]+dp[to[u]];
		}
		bool f=0;
		for(int i=v[x];i>=0;i--){
			if(a[x][i]){
				f=1;dp[x]=tot-i;
				break;
			}
		}
		if(!f)puts("IMPOSSIBLE"),exit(0);
	}
}
int main(){
	splay(n);
	for(int i=2;i<=n;i++){
		int x;splay(x);
		add(x,i);
	}
	for(int i=1;i<=n;i++){
		splay(v[i]);
	}
	dfs(1);
	puts("POSSIBLE");
}