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

void chmin(int& a, int b){
    a = min(a, b);
}

int N;
vector<int> child[1000];
int X[1000];

int dp[1000], sub[5001], sub2[5001];

const int INF = 1e8;

void dfs(int i){
    for(int j : child[i]) dfs(j);
    for(int j=0; j<=5000; j++) sub[j] = INF;
    sub[0] = 0;
    for(int j : child[i]){
        for(int j=0; j<=5000; j++) sub2[j] = INF;
        int s = X[j] + dp[j]; 
        for(int k=0; k<=5000; k++) for(int v : {X[j], dp[j]}) if(k+v<=5000) chmin(sub2[k+v], sub[k] + s - v);
        for(int j=0; j<=5000; j++) sub[j] = sub2[j];
    }
    dp[i] = INF;
    for(int j=0; j<=X[i]; j++) chmin(dp[i], sub[j]);
    if(dp[i] == INF){
        cout << "IMPOSSIBLE" << endl;
        exit(0);
    }
}

int main(){
    cin >> N;
    for(int i=1; i<N; i++){
        int p;
        cin >> p;
        child[p-1].push_back(i);
    }
    for(int i=0; i<N; i++) cin >> X[i];

    dfs(0);
    cout << "POSSIBLE" << endl;
}