#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

int n,l,r,i,j,k,a[100],ans=0,t,x,tot=0,que=0,duo=0;

void init()
{
	freopen("groupa.in","r",stdin);
	freopen("groupa.out","w",stdout);
	scanf("%d",&n);
	for (i=1;i<=n;i++)
	{
		scanf("%d",&a[i]);
		tot+=a[i];
	}
	scanf("%d%d",&l,&r);
	for (i=1;i<=n;i++)
	{
		if (a[i]<l) que+=l-a[i];
		if (a[i]>r) duo+=a[i]-r;
	}
}

void solve()
{
	t=tot/n;
	if (t<l || t>r || t==r&&tot %n)
	{
		printf("-1\n");
		return;
	}
	printf("%d\n",max(duo,que));
}

int main()
{
	init();
	solve();
	return 0;
}