#include <cstdio>
#include <vector>
#include <cstring>
#include <iostream>
using namespace std;
#define INF 0x3f3f3f3f

const int MAXN = 1000;
int n , x[ MAXN + 5 ] , f[ MAXN + 5 ] , dp[ 5 * MAXN + 5 ];
vector< int > Graph[ MAXN + 5 ];

void dfs( int u ) {
	for( int i = 0 ; i < Graph[ u ].size( ) ; i ++ ) dfs( Graph[ u ][ i ] );
	memset( dp , 0x3f , sizeof( dp ) ); dp[ 0 ] = 0;
	for( int i = 0 ; i < Graph[ u ].size( ) ; i ++ ) {
		int v = Graph[ u ][ i ];
		
		for( int j = x[ u ] ; j >= 0 ; j -- ) {
			int tmp = INF;
			if( j >= x[ v ] ) tmp = min( tmp , dp[ j - x[ v ] ] + f[ v ] );
			if( j >= f[ v ] ) tmp = min( tmp , dp[ j - f[ v ] ] + x[ v ] );
			dp[ j ] = tmp;
		}
	}
	for( int i = x[ u ] ; i >= 0 ; i -- )
		f[ u ] = min( f[ u ] , dp[ i ] );
}

int main( ) {
	scanf("%d",&n);
	for( int i = 2 , fa ; i <= n ; i ++ ) {
		scanf("%d",&fa);
		Graph[ fa ].push_back( i );
	}
	for( int i = 1 ; i <= n ; i ++ )
		scanf("%d",&x[ i ]);
	
	memset( f , 0x3f , sizeof( f ) );
	dfs( 1 );
	
	puts( f[ 1 ] < INF ? "POSSIBLE" : "IMPOSSIBLE" );
	return 0;
}