//https://mrsrz.github.io/2020/03/13/ARC083E/
#include<cstdio>
#include<bitset>
#include<vector>
#include<cstdlib>
using namespace std;
const int N=1145;
int n,fa[N],X[N],a[N];
vector<int>G[N];
bitset<5001>b;
void dfs(int now){
    int sum=0;
    for(int to:G[now])dfs(to),sum+=a[to];
    b.reset();
    b.set(0);
    for(int to:G[now])b=(b<<X[to])|(b<<(a[to]-X[to]));
    int x=-1;
    for(int i=X[now];i>=0&&x==-1;--i)if(b.test(i))x=i;
    if(x==-1)exit(puts("IMPOSSIBLE")*0);
    a[now]=sum+X[now]-x;
}
int main(){
    scanf("%d",&n);
    for(int i=2;i<=n;++i)
        scanf("%d",fa+i),G[fa[i]].push_back(i);
    for(int i=1;i<=n;++i)scanf("%d",X+i);
    dfs(1);
    puts("POSSIBLE");
    return 0;
}