#include <bits/stdc++.h>
#define inf 0x3f3f
using namespace std;
const int maxn=1e3+10;
vector<int>g[maxn];
int n,x[maxn];
int dp[maxn][5010],f[5010];
int dfs(int p){
    dp[p][0]=0;
    for (auto u:g[p]){
        int w=dfs(u),v=x[u];

        memcpy(f,dp[p],sizeof(f));
        memset(dp[p],0x3f3f,sizeof(dp[p]));

        for (int i=0; i<=x[p]; i++){
            if(i+w<=x[p])
                dp[p][i+w]=min(dp[p][i+w],f[i]+v);
            if(i+v<=x[p])
                dp[p][i+v]=min(dp[p][i+v],f[i]+w);
        }
    }
    int ans=dp[0][0];
    for (int i=0; i<=x[p]; i++)
        ans=min(dp[p][i],ans);
    return ans;
}

int main(){
    scanf("%d",&n);
    memset(dp,0x3f3f,sizeof(inf));
    for (int p,i=2; i<=n; i++) {
        scanf("%d",&p);
        g[p].push_back(i);
    }
    for (int i=1; i<=n; i++) scanf("%d",&x[i]);
    int ans=dfs(1);
    if(ans<dp[0][0])puts("POSSIBLE");
    else puts("IMPOSSIBLE");
    return 0;

}
