#pragma GCC optimize ("O3")

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <set>
#include <algorithm>
#include <numeric>
using namespace std;

using QWORD  = uint64_t;
using SQWORD = int64_t;
using DWORD  = uint32_t;
using SDWORD = int32_t;
using WORD   = uint16_t;
using SWORD  = int16_t;
using BYTE   = uint8_t;
using SBYTE  = int8_t;
using DOUBLE = double;
using FLOAT  = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD  (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD  (0xFFFFFFFF)
#define MAX_WORD   (0xFFFF)
#define MAX_BYTE   (0xFF)


#define ArrayLength(a)  (sizeof(a) / sizeof(a[0]))

static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS   (8)
#define WORD_BITS   (16)
#define DWORD_BITS  (32)
#define QWORD_BITS  (64)

using M_BOOL = bool;
#define M_TRUE (true)
#define M_FALSE (false)
#define DIVISOR (1000000007)

static inline void inputString(char *pcStr)
{
    char *pcCur = pcStr;
    for (;;) {
        char c = getchar();
        if (('\n' == c) || (EOF == c)) {
            break;
        }
        *pcCur = c;
        pcCur++;
    }
    *pcCur = '\0';
}


static inline SQWORD inputSQWORD(void)
{
    SQWORD sqNumber = 0;
    SQWORD sqMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                sqMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            sqNumber *= 10LL;
            sqNumber += (SQWORD)(c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return sqNumber * sqMultiplier;
            }
        }
    }
}


static inline SDWORD inputSDWORD(void)
{
    SDWORD lNumber = 0;
    SDWORD lMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                lMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            lNumber *= 10;
            lNumber += (c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return lNumber * lMultiplier;
            }
        }
    }
}

static inline DOUBLE inputFP(void)
{
    DOUBLE dInt = 0.0;
    DOUBLE dFrac = 0.0;
    DOUBLE dMultiplier = 1.0;
    DWORD dwFpCnt = 0;
    DOUBLE *pdCur = &dInt;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                dMultiplier = -1;
            }
        }
        if ('.' == c) {
            pdCur = &dFrac;
        } else if (('0' <= c) && (c <= '9')) {
            (*pdCur) *= 10;
            (*pdCur) += (DOUBLE)(c - '0');
            bRead = M_TRUE;
            if (pdCur == &dFrac) {
                dwFpCnt++;
            }
        } else {
            if (bRead) {
                return dMultiplier * (dInt + dFrac / (pow((DOUBLE)10.0 , (DOUBLE)dwFpCnt)));
            }
        }
    }
}

#define MAX_PNT (5000)
#define MAX_NODE (1000)

static vector<vector<SDWORD>> vvChilds(MAX_NODE + 1, vector<SDWORD>(0));
static vector<SDWORD>  vlPnts(MAX_NODE + 1);

/* 自ノードを白で塗ったとする(反転しても結果は同じ) */
typedef struct {
    SQWORD  sqPntWhite;
    SQWORD  sqPntBlack;
} ST_PNTS;

#define SDWORD_INF  (1000000000)

static bool visitNode(SDWORD lNodeNo, ST_PNTS &stRet)
{
    vector<ST_PNTS> vstChildPnt; 
    for (auto it: vvChilds[lNodeNo]) {
        ST_PNTS stChildPnt;
        if (!visitNode(it, stChildPnt)) {
            return false;
        }
        vstChildPnt.emplace_back(stChildPnt);
    }

    SDWORD lCurrentNodePnt = vlPnts[lNodeNo];
    set<SDWORD> setPnts;
    SDWORD lTtlPnt = 0;
    setPnts.insert(0);
    for (auto stChildPnt: vstChildPnt) {
        set<SDWORD> setPntsNext;
        for (auto lPnt: setPnts) {
            SDWORD lPntB = lPnt + (SDWORD)stChildPnt.sqPntBlack;
            SDWORD lPntW = lPnt + (SDWORD)stChildPnt.sqPntWhite;
            if (lPntB <= lCurrentNodePnt) {
                setPntsNext.insert(lPntB);
            }
            if (lPntW <= lCurrentNodePnt) {
                setPntsNext.insert(lPntW);
            }
        }
        lTtlPnt += (stChildPnt.sqPntBlack + stChildPnt.sqPntWhite);
        swap(setPntsNext, setPnts);
    }

    if (0 == setPnts.size()) {
        return false;
    } else {
        auto it = setPnts.end();
        it--;
        SDWORD lMaxPnt = *it;
        stRet.sqPntWhite = lCurrentNodePnt;
        stRet.sqPntBlack = lTtlPnt - lMaxPnt;
        return true;
    }
}

int main()
{
    /* 順方向にDPをしてM個の商品の選び方を求める */
    SQWORD sqInput_N = inputSQWORD();

    /* lpoint */
    for (SDWORD lChild = 2; lChild <= sqInput_N; lChild++) {
        SDWORD lParent = inputSDWORD();

        vvChilds[lParent].emplace_back(lChild);
    }
    for (SDWORD lNodeNo = 1; lNodeNo <= sqInput_N; lNodeNo++) {
        SDWORD lPoint = inputSDWORD();
        vlPnts[lNodeNo] = lPoint;
    }

    ST_PNTS stPnt;
    if (visitNode(1, stPnt)) {
        printf("POSSIBLE\n");
    } else {
        printf("IMPOSSIBLE\n");
    }

    return 0;
}

Measured memory_bytes: 512