#include <bits/stdc++.h>
using namespace std;
const int Imx = 2147483647;
const long long Lbig = 2e18;
const int mod = 1e9 + 7;
struct fastio {
  char s[100000];
  int it, len;
  fastio() { it = len = 0; }
  inline char get() {
    if (it < len) return s[it++];
    it = 0;
    len = fread(s, 1, 100000, stdin);
    if (len == 0)
      return EOF;
    else
      return s[it++];
  }
  bool notend() {
    char c = get();
    while (c == ' ' || c == '\n') c = get();
    if (it > 0) it--;
    return c != EOF;
  }
} _buff;
inline long long getnum() {
  long long r = 0;
  bool ng = 0;
  char c;
  c = _buff.get();
  while (c != '-' && (c < '0' || c > '9')) c = _buff.get();
  if (c == '-') ng = 1, c = _buff.get();
  while (c >= '0' && c <= '9') r = r * 10 + c - '0', c = _buff.get();
  return ng ? -r : r;
}
template <class T>
inline void putnum(T x) {
  if (x < 0) putchar('-'), x = -x;
  register short a[20] = {}, sz = 0;
  while (x) a[sz++] = x % 10, x /= 10;
  if (sz == 0) putchar('0');
  for (int i = sz - 1; i >= 0; i--) putchar('0' + a[i]);
}
inline char getreal() {
  char c = _buff.get();
  while (c == ' ' || c == '\n') c = _buff.get();
  return c;
}
int dp[1011][5011], ndp[5011];
int n, p[1011], w[1011], sz[1011];
vector<int> son[1011];
void check(int x) {
  for (int i = 0; i <= sz[x]; i++) {
    if (dp[x][i] <= 5000) return;
  }
  puts("IMPOSSIBLE");
  exit(0);
}
int main() {
  n = getnum();
  for (int i = 2; i <= n; i++) p[i] = getnum(), son[p[i]].push_back(i);
  for (int i = 1; i <= n; i++) w[i] = getnum();
  memset(dp, 31, sizeof(dp));
  for (int x = n; x >= 1; x--) {
    dp[x][0] = 0;
    for (int i = 0; i < son[x].size(); i++) {
      int u = son[x][i];
      for (int t = 0; t <= sz[x] + sz[u]; t++) ndp[t] = mod;
      for (int tx = 0; tx <= sz[x]; tx++) {
        for (int ty = 0; ty <= sz[u] && tx + ty <= 5000; ty++) {
          ndp[tx + ty] = min(ndp[tx + ty], dp[x][tx] + dp[u][ty]);
        }
      }
      for (int t = 0; t <= sz[x] + sz[u]; t++) dp[x][t] = ndp[t];
      sz[x] += sz[u];
      sz[x] = min(sz[x], 5000);
      check(x);
    }
    memset(ndp, 31, sizeof(ndp));
    for (int t = 0; t <= w[x]; t++) ndp[w[x]] = min(ndp[w[x]], dp[x][t]);
    for (int t = 0; t <= sz[x]; t++)
      if (dp[x][t] <= w[x]) ndp[t] = min(ndp[t], w[x]);
    sz[x] = max(sz[x], w[x]);
    for (int t = 0; t <= sz[x]; t++) dp[x][t] = ndp[t];
    check(x);
  }
  puts("POSSIBLE");
  return 0;
}
