#include<bits/stdc++.h>
using namespace std;

typedef long long LL;

const int N=1000,M=5000,INF=(1<<30)-1;

int n,x[N+9];
struct side{
  int y,next;
}e[N+9];
int lin[N+9],cs;

void Ins(int x,int y){e[++cs].y=y;e[cs].next=lin[x];lin[x]=cs;}

void into(){
  scanf("%d",&n);
  for (int i=2;i<=n;++i){
  	int x;
  	scanf("%d",&x);
  	Ins(x,i);
  }
  for (int i=1;i<=n;++i)
    scanf("%d",&x[i]);
}

int dp[N+9],dp0[M+9];

void Dfs_dp(int k,int fa){
  for (int i=lin[k];i;i=e[i].next)
    if (e[i].y^fa) Dfs_dp(e[i].y,k);
  dp[k]=INF;
  for (int i=0;i<=x[k];++i) dp0[i]=INF;
  dp0[0]=0;
  for (int i=lin[k];i;i=e[i].next)
    if (e[i].y^fa)
	  for (int j=x[k];j>=0;--j){
	  	int t=INF;
	  	if (j>=x[e[i].y]) t=min(t,dp0[j-x[e[i].y]]+dp[e[i].y]);
	  	if (j>=dp[e[i].y]) t=min(t,dp0[j-dp[e[i].y]]+x[e[i].y]);
	  	dp0[j]=t;
      }
  for (int i=0;i<=x[k];++i) dp[k]=min(dp[k],dp0[i]);
}

void work(){
  Dfs_dp(1,0);
}

void outo(){
  puts(dp[1]==INF?"IMPOSSIBLE":"POSSIBLE");
}

int main(){
  into();
  work();
  outo();
  return 0;
}
