#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
     
      
      
using namespace std;
template<typename T1, typename T2>inline void chkmin(T1 &x, T2 y) { if (x > y) x = y; }
template<typename T1, typename T2>inline void chkmax(T1 &x, T2 y) { if (x < y) x = y; }
/** Interface */
      
inline int readChar();
template <class T = int> inline T readInt(); 
template <class T> inline void writeInt( T x, char end = 0 );
inline void writeChar( int x ); 
inline void writeWord( const char *s );


      
/** Read */
      
static const int buf_size = 4096;
      
inline int getChar() {
    static char buf[buf_size];
    static int len = 0, pos = 0;
    if (pos == len) {
        pos = 0, len = fread(buf, 1, buf_size, stdin);
    }
    if (pos == len) {
        return -1;
    }
    return buf[pos++];
}                                                                                                                       
      
inline int readChar() {
    int c = getChar();
    while (c <= 32) {
        c = getChar();
    }
    return c;
}
      
template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}
      
/** Write */
      
static int write_pos = 0;
static char write_buf[buf_size];
      
inline void writeChar( int x ) {
    if (write_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
    write_buf[write_pos++] = x;
}
      
template <class T> 
inline void writeInt( T x, char end ) {
    if (x < 0)
        writeChar('-'), x = -x;
      
    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}
      
inline void writeWord( const char *s ) {     while (*s)
writeChar(*s++); }
      
struct Flusher {
    ~Flusher() {
        if (write_pos)
            fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
    }
} flusher;
#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left228
#define right right228
#define next next228
#define rank rank228
#define prev prev228
#define y1 y1228
#define ends ends228
#define begins begins228
const int MAXN = 1001;


int n;
int ps[MAXN], x[MAXN];
vector<int> g[MAXN];
bool dp[MAXN][MAXN * 5][2];
int can[2][2][MAXN * 5];


void dfs(int u) {
    for (auto h: g[u]) {
        dfs(h);
    }
    if (sz(g[u]) == 0) {
        dp[u][0][0] = true;
        dp[u][0][1] = true;
        return;
    }
    for (int curj = 0; curj < MAXN * 5; curj++) {
        can[1][0][curj] = x[u] + 1;
        can[1][1][curj] = x[u] + 1;
        can[0][0][curj] = x[u] + 1;
        can[0][1][curj] = x[u] + 1;
    }
    can[0][0][0] = 0;
    can[0][1][0] = 0;
    for (auto h: g[u]) {
        for (int p = 0; p < 2; p++) {
            for (int t = 0; t < MAXN * 5; t++) {
                if (dp[h][t][p]) {
                    for (int curj = 0; curj < MAXN * 5; curj++) {
                        if (can[0][p][curj] <= x[u]) {
                            chkmin(can[1][p][min(curj + t, MAXN * 5 - 1)], can[0][p][curj] + x[h]);
                        }
                        if (can[0][p ^ 1][curj] <= x[u]) {
                            chkmin(can[1][p ^ 1][min(curj + x[h], MAXN * 5 - 1)], can[0][p ^ 1][curj] + t);
                        }
                    }
                }
            }
        }
        for (int curj = 0; curj < MAXN * 5; curj++) {
            can[0][0][curj] = can[1][0][curj];
            can[0][1][curj] = can[1][1][curj];
            can[1][0][curj] = x[u] + 1;
            can[1][1][curj] = x[u] + 1;
        }
    }
    for (int curj = 0; curj < MAXN * 5; curj++) {
        for (int p = 0; p < 2; p++) {
            if (can[0][p][curj] <= x[u]) {
                dp[u][curj][p] = true;
            }
        }
    }
}


int main() {
    n = readInt();
    for (int i = 1; i < n; i++) {
        ps[i] = readInt();
        ps[i]--;
        g[ps[i]].push_back(i);
    }
    for (int i = 0; i < n; i++) {
        x[i] = readInt();
    }
    dfs(0);
    for (int curj = 0; curj < MAXN * 5; curj++) {
        if (dp[0][curj][0] || dp[0][curj][1]) {
            writeWord("POSSIBLE\n");
            return 0;
        }
    }
    writeWord("IMPOSSIBLE\n");
    return 0;   
}


Measured memory_bytes: 8064