#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
using namespace std;

#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

class mint {
    long long x;
public:
    mint(long long x = 0) : x((x% MOD + MOD) % MOD) {}
    mint operator-() const {
        return mint(-x);
    }
    mint& operator+=(const mint& a) {
        if ((x += a.x) >= MOD) x -= MOD;
        return *this;
    }
    mint& operator-=(const mint& a) {
        if ((x += MOD - a.x) >= MOD) x -= MOD;
        return *this;
    }
    mint& operator*=(const  mint& a) {
        (x *= a.x) %= MOD;
        return *this;
    }
    mint operator+(const mint& a) const {
        mint res(*this);
        return res += a;
    }
    mint operator-(const mint& a) const {
        mint res(*this);
        return res -= a;
    }
    mint operator*(const mint& a) const {
        mint res(*this);
        return res *= a;
    }

    mint operator^(const ll& t)const {
        if (!t) return 1;
        mint a = pow(t >> 1);
        a *= a;
        if (t & 1) a *= *this;
        return a;
    }

    mint pow(ll t) const {
        if (!t) return 1;
        mint a = pow(t >> 1);
        a *= a;
        if (t & 1) a *= *this;
        return a;
    }
    // for prime MOD
    mint inv() const {
        return pow(MOD - 2);
    }
    mint& operator/=(const mint& a) {
        return (*this) *= a.inv();
    }
    mint operator/(const mint& a) const {
        mint res(*this);
        return res /= a;
    }

    friend ostream& operator<<(ostream& os, const mint& m) {
        os << m.x;
        return os;
    }
};

//////////////////////////

int main() {
    
    ll N;
    cin >> N;

    vector<ll> P(N + 1), X(N + 1);
    for(ll i=2; i<=N; i++) cin >> P[i];
    repn(i, N) cin >> X[i];

    vector<vector<ll>> g(N+1);
    for(ll i=2; i<=N; i++) g[P[i]].push_back(i);

    vector<ll> dp(N + 1);

    string ans = "POSSIBLE";

    for (ll v = N; v >= 1; v--) {
        ll s = g[v].size();
        //cout << s << endl;
        vector<vector<ll>> sum(s + 1, vector<ll>(X[v] + 1,0));
        sum[0][0] = 1;

        repn(i, s) {
            ll w = g[v][i - 1];
            rep(j, X[v] + 1) {
                if (j >= X[w] && sum[i - 1][j - X[w]] == 1) { sum[i][j]=1; }
                if (j >= dp[w] && sum[i - 1][j - dp[w]] == 1) { sum[i][j] = 1; }
                //cout << i << j << sum[i][j] << endl;
            }
        }

        ll t = -1;
        rep(j, X[v] + 1) {
            if (sum[s][j] == 1) { t = j; }
        }

        if (t == -1) { ans = "IMPOSSIBLE"; break; }

        repn(i, s) {
            ll w = g[v][i - 1];
            dp[v] += X[w] + dp[w];
        }
        dp[v] -= t;
        //cout << v << dp[v] << endl;

    }

    cout << ans;
    

    system("PAUSE");
}

Measured memory_bytes: 2408