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

// template {{{
#define  range(i, l, r) for (int i = (int)(l); i < (int)(r); (i) += 1)
#define rrange(i, l, r) for (int i = (int)(r) - 1; i >= (int)(l); (i) -= 1)

#define  whole(f, x, ...) ([&](decltype((x)) container) { return (f)(  begin(container),  end(container), ## __VA_ARGS__); })(x)
#define rwhole(f, x, ...) ([&](decltype((x)) container) { return (f)( rbegin(container), rend(container), ## __VA_ARGS__); })(x)

#define debug(x) cerr << "(" << __LINE__ << ")" << #x << ": " << (x) << endl

using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;

// constexpr i32 mod   = 998244353;
constexpr i32 mod   = 1e9 + 7;
constexpr i32 inf   = 1001001001;
constexpr i64 infll = 1001001001001001001ll;

constexpr int dx[] = {0, -1, 1, 0, -1, 1, -1, 1};
constexpr int dy[] = {-1, 0, 0, 1, -1, -1, 1, 1};

struct IoSetup { IoSetup(int x = 15){ cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(x); cerr << fixed << setprecision(x); } } iosetup;

template <typename T = i64> T input() { T x; cin >> x; return x; }

template <typename T> ostream &operator<<(ostream &os, vector<T> &v) { range(i, 0, v.size()) { os << v[i] << (i + 1 != v.size() ? " " : ""); } return os; }
template <typename T> istream &operator>>(istream &is, vector<T> &v) { for (T &in : v) is >> in; return is; }

template <typename T1, typename T2> ostream &operator<<(ostream &os, pair<T1, T2> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
template <typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p) { is >> p.first >> p.second; return is; }

template <typename T> vector<T> make_vector(size_t a, T b) { return vector<T>(a, b); }
template <typename... Ts> auto make_vector(size_t a, Ts... ts) { return vector<decltype(make_vector(ts...))>(a, make_vector(ts...)); }

template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
// }}}

void solver() {
    int n = input();
    auto g = make_vector(n, 0, 0);
    range(i, 1, n) {
        int p = input() - 1;
        g[p].emplace_back(i);
    }

    vector< int > xs(n);
    cin >> xs;

    vector< int > ws(n, inf);
    function<bool(int)> dfs = [&](int v) {
        if (g[v].size() == 0) {
            ws[v] = 0;
            return true;
        }

        for (auto u: g[v]) {
            if (!dfs(u)) return false;
        }

        vector< int > dp(xs[v] + 1, inf);
        int u = g[v][0];
        if (xs[v] >= xs[u]) dp[xs[u]] = ws[u];
        if (xs[v] >= ws[u]) dp[ws[u]] = xs[u];

        range(i, 1, g[v].size()) {
            int u = g[v][i];

            rrange(t, 0, dp.size()) {
                int p = t + xs[u];
                int q = t + ws[u];

                if (p > xs[v] && q > xs[v]) {
                    dp[t] = inf;
                }

                if (dp[t] == inf) continue;

                int d = dp[t];
                dp[t] = inf;

                if (p <= xs[v]) chmin(dp[p], d + ws[u]);
                if (q <= xs[v]) chmin(dp[q], d + xs[u]);
            }
        }

        ws[v] = *whole(min_element, dp);

        return ws[v] != inf;
    };

    cout << (dfs(0) ? "POSSIBLE" : "IMPOSSIBLE") << endl;
}

signed main(int argc, char *argv[]) {
    solver();
}


Measured memory_bytes: 3764