#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto& (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define sar(a,n) cout<<#a<<":";rep(pachico,n)cout<<" "<<a[pachico];cout<<endl

using namespace std;

template<typename S,typename T>auto&operator<<(ostream&o,pair<S,T>p){return o<<"{"<<p.fi<<","<<p.se<<"}";}
template<typename T>auto&operator<<(ostream&o,set<T>s){for(auto&e:s)o<<e<<" ";return o;}
template<typename S,typename T,typename U>
auto&operator<<(ostream&o,priority_queue<S,T,U>q){while(!q.empty())o<<q.top()<<" ",q.pop();return o;}
template<typename K,typename T>auto&operator<<(ostream&o,map<K,T>&m){for(auto&e:m)o<<e<<" ";return o;}
template<typename T>auto&operator<<(ostream&o,vector<T>v){for(auto&e:v)o<<e<<" ";return o;}
void ashow(){cout<<endl;}template<typename T,typename...A>void ashow(T t,A...a){cout<<t<<" ";ashow(a...);}
template<typename S,typename T,typename U>
struct TRI{S fi;T se;U th;TRI(){}TRI(S f,T s,U t):fi(f),se(s),th(t){}};
template<typename S,typename T,typename U>
auto&operator<<(ostream&o,TRI<S,T,U>&t){return o<<"{"<<t.fi<<","<<t.se<<","<<t.th<<"}";}

typedef pair<int, int> P;
typedef pair<ll, ll> pll;
typedef TRI<int, int, int> tri;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<P> vp;
typedef vector<double> vd;
typedef vector<string> vs;

const int MAX_N = 1005;

vector<int> G[MAX_N];
int x[MAX_N];
// 色 j を根としたときのもう一方の最小
int res[MAX_N][2];

bool dfs(int u, int p)
{
    // 根が i で根以外の色 i の和が j のときのもう一方の最小値
    vvi dp0(2, vi(x[u]+1, INF)), dp1(2, vi(x[u]+1, INF));
    dp0[0][0] = dp1[0][0] = 0;
    for(int v : G[u]){
        if(v != p){
            if(!dfs(v, u)) return false;
            rep(i,x[u]+1){
                dp0[1][i] = dp1[1][i] = INF;
            }
            rep(i,x[u]+1){
                if(i+x[v] <= x[u]){
                    cmn(dp0[1][i+x[v]], dp0[0][i]+res[v][0]);
                }
                if(i+res[v][1] <= x[u]){
                    cmn(dp0[1][i+res[v][1]], dp0[0][i]+x[v]);
                }
                if(i+x[v] <= x[u]){
                    cmn(dp1[1][i+x[v]], dp1[0][i]+res[v][1]);
                }
                if(i+res[v][0] <= x[u]){
                    cmn(dp1[1][i+res[v][0]], dp1[0][i]+x[v]);
                }
            }
            swap(dp0[0], dp0[1]);
            swap(dp1[0], dp1[1]);
        }
    }
    int res0 = *min_element(all(dp0[0]));
    int res1 = *min_element(all(dp0[0]));
    if(res0 == INF && res1 == INF) return false;
    res[u][0] = res0, res[u][1] = res1;
    return true;
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    rep(i,n-1){
        int p;
        cin >> p;
        G[i+1].pb(p-1), G[p-1].pb(i+1);
    }
    rep(i,n){
        cin >> x[i];
    }
    rep(i,n){
        rep(j,2){
            res[i][j] = INF;
        }
    }
    if(dfs(0, -1)){
        cout << "POSSIBLE\n";
    }else{
        cout << "IMPOSSIBLE\n";
    }
    return 0;
}


Measured memory_bytes: 22092