// 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);
    if (t > 5000) {
        puts("IMPOSSIBLE");
        exit(0);
    }
    // printf("dfs(%d)=%d\n", u, t);
    return t;
}

void solve()
{
    dfs(1);
    puts("POSSIBLE");
}

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》
