#include<iostream>
#include<cstdio>
using namespace std;
int n,sum,tot,t,a[10000005],ans;
int main()
{   freopen("groupa.in","r",stdin);
    freopen("groupa.out","w",stdout);
    cin>>n;
    for(int i=1;i<=n;i++)
    {
    	cin>>a[i];
    	t+=a[i];
	}
	int l,r;;
	cin>>l>>r;
	for(int i=1;i<=n;i++)
	{
		if(a[i]>r)
		{
			sum+=a[i]-r;
		}
		if(a[i]<l)
		{
			tot+=l-a[i];
		}
	}
	ans=max(sum,tot);
	if(t>n*r||t<n*l)
	{cout<<"-1";}
	else cout<<ans;
	
	return 0;
}