#include <bits/stdc++.h>
using ull = unsigned long long int;
using ll = long long;
using ld = long double;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;
using vi = std::vector<int>;
using vvi = std::vector<vi>;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vd = std::vector<double>;
using vvd = std::vector<vd>;
using qi = std::queue<int>;
using vpii = std::vector<std::pair<int, int>>;
using vpll = std::vector<pll>;
using namespace std;
const int Mod = (1e9) + 7;
const int INF = 1e9 + 19;
const ll INFL = 1e18 + 19;
const int dx[] = {-1, 0, 0, 1};
const int dy[] = {0, -1, 1, 0};
const int dx2[] = {-1, -1, -1, 0, 0, 0, 1, 1, 1};
const int dy2[] = {1, 0, -1, 1, 0, -1, 1, 0, -1};
const double EPS = 1e-10;
template <class T1, class T2>
inline void chmin(T1& a, T2 b) {
  if (a > b) a = b;
}
template <class T1, class T2>
inline void chmax(T1& a, T2 b) {
  if (a < b) a = b;
}
template <class T>
inline void pri(T a) {
  cout << a << endl;
}
template <class Z>
using vec = vector<Z>;
template <class T>
using min_priority_queue = priority_queue<T, vector<T>, greater<T>>;
template <class T1, class T2>
void update(T1& a, T2 b) {
  a += b;
  if (a > Mod) a %= Mod;
}
inline void IN(void) { return; }
template <typename First, typename... Rest>
void IN(First& first, Rest&... rest) {
  cin >> first;
  IN(rest...);
  return;
}
inline void OUT(void) {
  cout << "\n";
  return;
}
template <typename First, typename... Rest>
void OUT(First first, Rest... rest) {
  cout << first << " ";
  OUT(rest...);
  return;
}
bool pairsort(pll pl, pll pr) {
  if (pl.first == pr.first) return pl.second > pr.second;
  return pl.first < pr.first;
}
int cntbit(ll a, int n, int j) {
  int res = 0;
  for (int(i) = (j); (i) < (n); (i)++) {
    if (a >> i & 1) {
      res++;
    }
  }
  return res;
}
vector<int> make_bit(int a) {
  vector<int> res;
  for (int i = 31; i >= 0; i--)
    if (a & (1 << i)) res.push_back(i);
  return res;
}
bool stdbit(int a, int b) { return a & (1 << b); }
int GCD(int a, int b) {
  if (b > a) return GCD(b, a);
  if (a % b == 0)
    return b;
  else
    return GCD(b, a % b);
}
int LCM(int a, int b) { return a * b / GCD(a, b); }
int roundup(int a, int b) {
  if (a % b == 0)
    return a / b;
  else
    return (a + b) / b;
}
int rounddown(int a, int b) {
  if (a % b == 0)
    return a / b;
  else {
    return (a - b) / b;
  }
}
ll pow(ll a, ll n) {
  ll res = 1;
  while (n > 0) {
    if (n & 1) res *= a;
    a *= a;
    n = n >> 1;
  }
  return res;
}
ll GetDiviserCount(ll N) {
  ll res = 1;
  for (int(i) = (2); (i) < (sqrt(N) + 1); (i)++) {
    ll cnt = 0;
    while (N % i == 0) {
      cnt++;
      N /= i;
    }
    res *= (cnt + 1);
    if (N == 1) break;
  }
  if (N != 1) res *= 2;
  return res;
}
vll GetDivisor(ll N) {
  vll res;
  for (ll i = 1; i * i <= N; i++) {
    if (N % i == 0) {
      res.push_back(i);
      if (i * i != N) res.push_back(N / i);
    }
  }
  sort((res).begin(), (res).end());
  return res;
}
struct Modint {
  using ll = long long int;
  ll x;
  Modint(ll x = 0) : x((x % Mod + Mod) % Mod) {}
  Modint operator-() { return Modint(-x); }
  Modint& operator+=(Modint a) {
    x += a.x;
    if (x >= Mod) x -= Mod;
    return *this;
  }
  Modint& operator-=(Modint a) {
    if (x < a.x) x += Mod;
    x -= a.x;
    return *this;
  }
  Modint& operator*=(Modint a) {
    (x *= a.x) %= Mod;
    return *this;
  }
  Modint operator+(Modint a) {
    Modint b(*this);
    b += a;
    return b;
  }
  Modint operator-(Modint a) {
    Modint b(*this);
    b -= a;
    return b;
  }
  Modint operator*(Modint a) {
    Modint b(*this);
    b *= a;
    return b;
  }
  long long int EXTGCD(long long int a, long long int b, long long int& x,
                       long long int& y) {
    if (b == 0) {
      x = 1;
      y = 0;
      return a;
    }
    long long int g = EXTGCD(b, a % b, y, x);
    y -= (a / b) * x;
    return g;
  }
  Modint inverse() {
    long long int a, b;
    EXTGCD(x, Mod, a, b);
    a %= Mod;
    return a;
  }
  Modint pow(ll a) {
    Modint res = 1;
    Modint b = x;
    while (a > 0) {
      if (a & 1) res *= b;
      a = a >> 1;
      b *= b;
    }
    return res;
  }
  friend ostream& operator<<(ostream& os, const Modint& a);
};
ostream& operator<<(ostream& os, const Modint& a) {
  os << a.x;
  return os;
}
struct combination {
  vector<Modint> fact, ifact;
  combination(int n) : fact(n + 1), ifact(n + 1) {
    fact[0] = 1;
    for (int i = 1; i <= n; i++) fact[i] = fact[i - 1] * i;
    ifact[n] = fact[n].inverse();
    for (int i = n; i >= 1; i--) ifact[i - 1] = ifact[i] * i;
  }
  Modint operator()(int n, int k) { return fact[n] * ifact[n - k] * ifact[k]; }
};
using vm = vector<Modint>;
using vvm = vector<vm>;
template <class Z>
struct MyMatrix {
  using mat = MyMatrix<Z>;
  vector<vector<Z>> m_dat;
  int m_h;
  int m_w;
  MyMatrix(int h, int w) : m_h(h), m_w(w), m_dat(h, vector<Z>(w)) {}
  vector<Z>& operator[](int idx) { return m_dat[idx]; }
  mat Multiple(mat& a) {
    mat C(m_h, a.m_w);
    for (int i = 0; i < m_h; i++) {
      for (int j = 0; j < a.m_w; j++) {
        for (int k = 0; k < m_w; k++) {
          C[i][j] += m_dat[i][k] * a[k][j];
        }
      }
    }
    return C;
  }
  mat Pow(ll x) {
    mat B(m_h, m_w);
    for (int i = 0; i < m_h; i++) {
      B[i][i] = 1;
    }
    mat A = *this;
    while (x > 0) {
      if (x & 1) B = B.Multiple(A);
      A = A.Multiple(A);
      x = x >> 1;
    }
    return B;
  }
};
template <class T>
using mat = MyMatrix<T>;
const int max_n = 3 * (1e5) + 1;
const int max_m = 83 * (1e5) + 1;
int n, m, k;
ll N;
int h, w;
string S;
int a, b, c;
vi v;
int ans;
double x, y, z;
vector<int> G[1010101];
vector<int> dp;
vi X;
bool ok = true;
void dfs(int curr, int prev = -1) {
  set<int> pres;
  int sum = 0;
  for (auto(to) : (G[curr])) {
    if (to == prev) continue;
    dfs(to, curr);
    set<int> nex;
    sum += X[to] + dp[to];
    if (pres.size() == 0) {
      nex.insert(-dp[to]);
      nex.insert(-X[to]);
    } else {
      for (auto(itr) : (pres)) {
        int k = itr - dp[to];
        int k2 = itr - X[to];
        nex.insert(k2);
        nex.insert(k);
      }
    }
    for (auto(itr) : (nex)) {
      pres.insert(itr);
    }
  }
  if (pres.size() == 0) {
    pres.insert(0);
  }
  auto p = pres.lower_bound(-X[curr]);
  if (p == pres.end()) {
    ok = false;
    return;
  }
  int x = *p;
  dp[curr] = sum + x;
}
void solve() {
  IN(n);
  for (int(i) = 0; (i) < (n - 1); (i)++) {
    IN(a);
    a--;
    G[a].emplace_back(i + 1);
    G[i + 1].emplace_back(a);
  }
  X = dp = vi(n + 1);
  for (int(i) = 0; (i) < (n); (i)++) IN(X[i]);
  dfs(0);
  if (ok) {
    pri("POSSIBLE");
  } else
    pri("IMPOSSIBLE");
}
signed main(int argc, char* argv[]) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int cases = 1;
  while (cases--) solve();
  return 0;
}
