#include <bits/stdc++.h>
using namespace std;
const int N = 1e3 + 3, M = 5e3 + 2;
vector<int> g[N];
int X[N], ok = 1;
int dp[N];
void dfs(int v) {
  int sum = 0, yes = 0;
  for (auto it : g[v]) {
    dfs(it), sum += dp[it] + X[it];
    if (X[it] == 0 || dp[it] == 0) yes = 1;
  }
  bool tmp1[M], tmp2[M];
  memset(tmp1, 0, sizeof(tmp1));
  tmp1[0] = 1;
  for (int it : g[v]) {
    memset(tmp2, 0, sizeof(tmp2));
    for (int i = M - 1; i >= 0; i--) {
      if (tmp1[i]) {
        if (i + dp[it] < M) tmp2[i + dp[it]] = 1;
        if (i + X[it] < M) tmp2[i + X[it]] = 1;
      }
    }
    for (int i = 0; i < M; i++) tmp1[i] = tmp2[i];
  }
  if (yes || g[v].size() == 0)
    tmp1[0] = 1;
  else
    tmp1[0] = 0;
  for (int i = X[v]; i >= 0; i--) {
    if (tmp1[i]) {
      dp[v] = sum - i;
      if (dp[v] < 0) abort();
      return;
    }
  }
  ok = 0;
}
int main() {
  int n;
  cin >> n;
  for (int i = 2; i <= n; i++) {
    int x;
    scanf("%d", &x);
    g[x].push_back(i);
  }
  for (int i = 1; i <= n; i++) scanf("%d", &X[i]);
  dfs(1);
  puts(ok ? "POSSIBLE" : "IMPOSSIBLE");
}
