#include <bits/stdc++.h>
using namespace std;
int X[1010];
vector<int> ch[1010];
pair<int, int> dfs(int root) {
  vector<int> dp(5010, 1e9);
  dp[0] = 0;
  for (int c : ch[root]) {
    vector<int> ndp(5010, 1e9);
    int w, b;
    tie(w, b) = dfs(c);
    for (int i = 5000; i >= X[c]; i--) {
      ndp[i] = min(ndp[i], dp[i - X[c]] + w);
    }
    for (int i = 5000; i >= b; i--) {
      ndp[i] = min(ndp[i], dp[i - b] + X[c]);
    }
    dp = ndp;
  }
  int minB = 1000000000, minW = 1000000000;
  for (int i = 0; i <= X[root]; i++) minW = min(dp[i], minW);
  for (int i = 0; i <= 5000; i++)
    if (dp[i] <= X[root]) {
      minB = min(i, minB);
    }
  return make_pair(minW, minB);
}
int main() {
  int N;
  cin >> N;
  for (int i = 1; i < N; i++) {
    int p;
    cin >> p;
    ch[--p].push_back(i);
  }
  for (int i = 0; i < N; i++) cin >> X[i];
  auto p = dfs(0);
  int mn = min(p.first, p.second);
  if (mn < 1e9)
    cout << "POSSIBLE" << endl;
  else
    cout << "IMPOSSIBLE" << endl;
}
