// Copyright (C) 2017 __debug.
     
    // This program is free software; you can redistribute it and/or
    // modify it under the terms of the GNU General Public License as
    // published by the Free Software Foundation; version 3
     
    // This program is distributed in the hope that it will be useful,
    // but WITHOUT ANY WARRANTY; without even the implied warranty of
    // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    // GNU General Public License for more details.
     
    // You should have received a copy of the GNU General Public License
    // along with this program; If not, see <http://www.gnu.org/licenses/>.
     
     
    #include <bits/stdc++.h>
    #include <ext/pb_ds/assoc_container.hpp>
    #include <ext/pb_ds/priority_queue.hpp>
     
    #define x first
    #define y second
    #define MP std::make_pair
    #define SZ(x) ((int)(x).size())
    #define ALL(x) (x).begin(), (x).end()
    #define DEBUG(...) fprintf(stderr, __VA_ARGS__)
    #ifdef __linux__
    #define getchar getchar_unlocked
    #define putchar putchar_unlocked
    #endif
     
    using std::pair;
    using std::vector;
    using std::string;
     
    typedef long long LL;
    typedef pair<int, int> Pii;
     
    const int oo = 0x3f3f3f3f;
     
    template<typename T> inline bool chkmax(T &a, T b) { return a < b ? a = b, true : false; }
    template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, true : false; }
    string procStatus()
    {
        std::ifstream t("/proc/self/status");
        return string(std::istreambuf_iterator<char>(t), std::istreambuf_iterator<char>());
    }
    template<typename T> T read(T &x)
    {
        int f = 1;
        char ch = getchar();
        for (; !isdigit(ch); ch = getchar())
            f = (ch == '-' ? -1 : 1);
        for (x = 0; isdigit(ch); ch = getchar())
            x = 10 * x + ch - '0';
        return x *= f;
    }
    template<typename T> void write(T x)
    {
        if (x == 0) {
            putchar('0');
            return;
        }
        if (x < 0) {
            putchar('-');
            x = -x;
        }
        static char s[20];
        int top = 0;
        for (; x; x /= 10)
            s[++top] = x % 10 + '0';
        while (top)
            putchar(s[top--]);
    }
    // EOT
     
    const int MAXN = 1e3 + 5, RNG = 5e3 + 5;
     
    int N;
    int X[MAXN];
    vector<int> G[MAXN];
     
    void input()
    {
        read(N);
        for (int i = 2; i <= N; ++i) {
            int f;
            read(f);
            G[f].push_back(i);
        }
        for (int i = 1; i <= N; ++i) {
            read(X[i]);
        }
    }
     
    int dfs(int u)
    {
        int f[RNG], g[RNG];
     
        memset(f, +oo, sizeof(f));
        f[0] = 0;
        for (int i = 0; i < SZ(G[u]); ++i) {
            int v = G[u][i];
            int x = X[v], y = dfs(v);
            std::swap(f, g);
            memset(f, +oo, sizeof(f));
            for (int j = 0; j + x < RNG; ++j) {
                chkmin(f[j + x], g[j] + y);
            }
            for (int j = 0; j + y < RNG; ++j) {
                chkmin(f[j + y], g[j] + x);
            }
        }
     
        int t = *std::min_element(f, f + X[u] + 1);
        return t;
    }
     
    void solve()
    {
    if (dfs(1) != +oo)
        puts("POSSIBLE");
    else
        puts("IMPOSSIBLE");
    }
     
    int main()
    {
    #ifdef __DEBUG
        freopen("E.in", "r", stdin);
        freopen("E.out", "w", stdout);
    #endif
     
        input();
        solve();
    }
     
    // 东边日出西边雨，道是无晴却有晴。
    //     -- 刘禹锡《竹枝词二首·其一》

Measured memory_bytes: 17152