#include<bits/stdc++.h>
using namespace std;
int n,i,a[51],l,r,sum=0,sum_l=0,sum_r=0;
int main(){
	freopen("groupa.in","r",stdin);
	freopen("groupa.out","w",stdout);
	cin>>n;
	for(i=1;i<=n;i++){cin>>a[i];sum+=a[i];}
    cin>>l>>r;
	if(sum<l*n||sum>r*n)cout<<"-1";
	else
	{
		for(i=1;i<=n;i++)
		{
			if(a[i]>r)sum_r+=a[i]-r;
			if(a[i]<l)sum_l+=l-a[i];
		}
		cout<<max(sum_r,sum_l);
	}
    return 0;
}