// need
    #include <iostream>
    #include <algorithm>
     
    // data structure
    #include <bitset>
    //#include <list>
    #include <map>
    #include <queue>
    #include <set>
    #include <stack>
    #include <string>
    #include <utility>
    #include <vector>
    #include <array>
    //#include <tuple>
    //#include <unordered_map>
    //#include <unordered_set>
    #include <complex>
    //#include <deque>
    #include<valarray>
     
    // stream
    //#include <istream>
    //#include <sstream>
    //#include <ostream>
    //#include <fstream>
     
    // etc
    #include <cmath>
    #include <cassert>
    #include <functional>
    #include <iomanip>
    //#include <typeinfo>
    #include <chrono>
    #include <random>
    #include <numeric>
     
     
    #define INIT std::ios::sync_with_stdio(false);std::cin.tie(0);
    #define VAR(type, ...)type __VA_ARGS__;MACRO_VAR_Scan(__VA_ARGS__);
    template<typename T> void MACRO_VAR_Scan(T& t) { std::cin >> t; }
    template<typename First, typename...Rest>void MACRO_VAR_Scan(First& first, Rest&...rest) { std::cin >> first; MACRO_VAR_Scan(rest...); }
    #define VEC_ROW(type, n, ...)std::vector<type> __VA_ARGS__;MACRO_VEC_ROW_Init(n, __VA_ARGS__); for(int i=0; i<n; ++i){MACRO_VEC_ROW_Scan(i, __VA_ARGS__);}
    template<typename T> void MACRO_VEC_ROW_Init(int n, T& t) { t.resize(n); }
    template<typename First, typename...Rest>void MACRO_VEC_ROW_Init(int n, First& first, Rest&...rest) { first.resize(n); MACRO_VEC_ROW_Init(n, rest...); }
    template<typename T> void MACRO_VEC_ROW_Scan(int p, T& t) { std::cin >> t[p]; }
    template<typename First, typename...Rest>void MACRO_VEC_ROW_Scan(int p, First& first, Rest&...rest) { std::cin >> first[p]; MACRO_VEC_ROW_Scan(p, rest...); }
    #define OUT(d) std::cout<<d;
    #define FOUT(n, d) std::cout<<std::fixed<<std::setprecision(n)<<d;
    #define SOUT(n, c, d) std::cout<<std::setw(n)<<std::setfill(c)<<d;
    #define SP std::cout<<" ";
    #define TAB std::cout<<"\t";
    #define BR std::cout<<"\n";
    #define SPBR(i, n) std::cout<<(i + 1 == n ? '\n' : ' ');
    #define ENDL std::cout<<std::endl;
    #define FLUSH std::cout<<std::flush;
    #define VEC(type, c, n) std::vector<type> c(n);for(auto& i:c)std::cin>>i;
    #define MAT(type, c, m, n) std::vector<std::vector<type>> c(m, std::vector<type>(n));for(auto& r:c)for(auto& i:r)std::cin>>i;
    #define ALL(a) (a).begin(),(a).end()
    #define FOR(i, a, b) for(int i=(a);i<(b);++i)
    #define RFOR(i, a, b) for(int i=(b)-1;i>=(a);--i)
    #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 FORLL(i, a, b) for(ll i=ll(a);i<ll(b);++i)
    #define RFORLL(i, a, b) for(ll i=ll(b)-1;i>=ll(a);--i)
    #define REPLL(i, n) for(ll i=0;i<ll(n);++i)
    #define RREPLL(i, n) for(ll i=ll(n)-1;i>=0;--i)
    #define IN(a, x, b) (a<=x && x<b)
    #define SHOW(d) {std::cerr << #d << "\t:" << d << "\n";}
    #define SHOWVECTOR(v) {std::cerr << #v << "\t:";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
    #define SHOWVECTOR2(v) {std::cerr << #v << "\t:\n";for(const auto& xxx : v){for(const auto& yyy : xxx){std::cerr << yyy << " ";}std::cerr << "\n";}}
    #define SHOWQUEUE(a) {auto tmp(a);std::cerr << #a << "\t:";while(!tmp.empty()){std::cerr << tmp.front() << " ";tmp.pop();}std::cerr << "\n";}
    template<typename T> inline T CHMAX(T& a, const T b) { return a = (a < b) ? b : a; }
    template<typename T> inline T CHMIN(T& a, const T b) { return a = (a > b) ? b : a; }
    #define EXCEPTION(msg) throw std::string("Exception : " msg " [ in ") + __func__ + " : " + std::to_string(__LINE__) + " lines ]"
    #define TRY(cond, msg) try {if (cond) EXCEPTION(msg);}catch (std::string s) {std::cerr << s << std::endl;}
    void CHECKTIME(std::function<void()> f) { auto start = std::chrono::system_clock::now(); f(); auto end = std::chrono::system_clock::now(); auto res = std::chrono::duration_cast<std::chrono::nanoseconds>((end - start)).count(); std::cerr << "[Time:" << res << "ns  (" << res / (1.0e9) << "s)]\n"; }
     
    template<typename S, typename T>
    std::ostream& operator<<(std::ostream& os, std::pair<S, T> p) {
    	os << "(" << p.first << ", " << p.second << ")";
    	return os;
    }
     
    #define int ll
    using ll = long long;
    using ull = unsigned long long;
    using PAIR = std::pair<int, int>;
    using PAIRLL = std::pair<ll, ll>;
    constexpr int INFINT = 1 << 30;                          // 1.07x10^ 9
    constexpr int INFINT_LIM = (1LL << 31) - 1;              // 2.15x10^ 9
    constexpr ll INFLL = 1LL << 60;                          // 1.15x10^18
    constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);  // 9.22x10^18
    constexpr double EPS = 1e-7;
    constexpr int MOD = 1000000007;
    constexpr double PI = 3.141592653589793238462643383279;
     
     
     
    signed main() {
    	INIT;
    	VAR(int, n);
    	VEC(int, p, n - 1);
    	VEC(int, x, n);
     
    	std::vector<std::vector<int>> g(n);
    	REP(i, n - 1) {
    		--p[i];
    		g[i + 1].emplace_back(p[i]);
    		g[p[i]].emplace_back(i + 1);
    	}
    	std::vector<PAIR> w(n, PAIR(0, 0));
     
    	std::function<void(int, int)> dfs = [&](int v, int par) {
    		bool chi = true;
    		std::vector<int> p;
    		int sum = 0;
    		for (auto to : g[v]) {
    			if (to == par) continue;
    			chi = false;
    			dfs(to, v);
    			PAIR pa(w[to]);
    			int min = std::min(pa.first, pa.second);
    			sum += min;
    			pa.first -= min;
    			pa.second -= min;
    			int max = std::max(pa.first, pa.second);
    			if(max > 0) p.emplace_back(max);
    		}
    		if (chi) {
    			w[v] = PAIR(x[v], 0);
    			return;
    		}
    		int psum = 0;
    		REP(i, p.size()) psum += p[i];
    		int obj = x[v] - sum;
    		if (obj < 0) {
    			OUT("IMPOSSIBLE")BR;
    			exit(0);
    		}
    		std::vector<std::vector<bool>> dp(2, std::vector<bool>(obj + 1, false));
    		dp[0][0] = true;
    		REP(i, p.size()) {
    			int I = i % 2;
    			int II = (i + 1) % 2;
    			REP(j, obj + 1) {
    				if (!dp[I][j]) continue;
    				dp[II][j] = true;
    				if (j + p[i] <= obj) {
    					dp[II][j + p[i]] = true;
    				}
    			}
    		}
    		RREP(i, obj + 1) {
    			if (dp[0][i] || dp[1][i]) {
    				w[v] = PAIR(x[v], psum - i + sum);
    				return;
    			}
    		}
    	};
    	dfs(0, -1);
    	OUT("POSSIBLE")BR;
    	return 0;
    }//2

Measured memory_bytes: 512