#include<bits/stdc++.h>
const int N=1007,inf=0x3f3f3f3f;
int n,xs[N],ys[N],fa[N],f[5007],g[5007];
void mins(int&a,int b){if(a>b)a=b;}
void f1(int w){
	for(int u=w+1;u<=n;++u)if(fa[u]==w)f1(u);
	memset(f,0,sizeof(f));
	for(int u=w+1;u<=n;++u)if(fa[u]==w){
		memset(g,0x3f,sizeof(g));
		int x=xs[u],y=ys[u];
		for(int i=x;i<=xs[w];++i)mins(g[i],f[i-x]+y);
		for(int i=y;i<=xs[w];++i)mins(g[i],f[i-y]+x);
		memcpy(f,g,sizeof(g));
	}
	ys[w]=f[xs[w]];
}
int main(){
	scanf("%d",&n);
	for(int i=2;i<=n;++i)scanf("%d",fa+i);
	for(int i=1;i<=n;++i)scanf("%d",xs+i);
	f1(1);
	puts(ys[1]<inf?"POSSIBLE":"IMPOSSIBLE");
	return 0;
}