#include<bits/stdc++.h>
#define ll long long
#define inf 0x3f3f3f3f3f3f3f3fLL
using namespace std;
ll n,x,a[1005],f[1005][2],dp[2][5005],flag;
vector<ll> s[1005];
void dfs(ll rt)
{
	if(!s[rt].size())
	{
		f[rt][0] = f[rt][1] = 0;
		return;
	}
	f[rt][0] = f[rt][1] = inf;
	for(ll i = 0;i < s[rt].size();i++)
	    dfs(s[rt][i]);
	for(ll i = 0;i <= a[rt];i++)
	    dp[0][i] = dp[1][i] = inf;
	dp[1][0] = 0;
	for(ll i = 0;i < s[rt].size();i++)
	{
	    for(ll j = 0;j <= a[rt];j++)
	    {
	    	dp[i & 1][j] = inf;
	    	if(j >= f[s[rt][i]][1])
	            dp[i & 1][j] = min(dp[i & 1][j],dp[(i & 1) ^ 1][j - f[s[rt][i]][1]] + a[s[rt][i]]);
	    	if(j >= a[s[rt][i]])
	            dp[i & 1][j] = min(dp[i & 1][j],dp[(i & 1) ^ 1][j - a[s[rt][i]]] + f[s[rt][i]][0]);
		}
	}
	for(ll i = 0;i <= a[rt];i++)
    	f[rt][0] = min(f[rt][0],dp[(s[rt].size() - 1) & 1][i]);
	for(ll i = 0;i <= a[rt];i++)
	    dp[0][i] = dp[1][i] = inf;
	dp[1][0] = 0;
	for(ll i = 0;i < s[rt].size();i++)
	{
	    for(ll j = 0;j <= a[rt];j++)
	    {
	    	dp[i & 1][j] = inf;
	    	if(j >= f[s[rt][i]][0])
	            dp[i & 1][j] = min(dp[i & 1][j],dp[(i & 1) ^ 1][j - f[s[rt][i]][0]] + a[s[rt][i]]);
	    	if(j >= a[s[rt][i]])
	            dp[i & 1][j] = min(dp[i & 1][j],dp[(i & 1) ^ 1][j - a[s[rt][i]]] + f[s[rt][i]][1]);
		}
	}
	for(ll i = 0;i <= a[rt];i++)
    	f[rt][1] = min(f[rt][1],dp[(s[rt].size() - 1) & 1][i]);
    if(f[rt][0] == inf || f[rt][1] == inf)
        flag = 1;
}
int main()
{
	scanf("%lld",&n);
	for(ll i = 2;i <= n;i++)
	    scanf("%lld",&x),s[x].push_back(i);
	for(ll i = 1;i <= n;i++)
	    scanf("%lld",&a[i]);
	dfs(1);
	if(flag)
	    printf("IMPOSSIBLE\n");
	else
	    printf("POSSIBLE\n");
    return 0;
}