#include <iostream>
#include <cstdio>

using namespace std;

int n,a[55],l,r,sum;

int main()
{
	freopen("groupa.in","r",stdin);
	freopen("groupa.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)scanf("%d",&a[i]),sum+=a[i];
	scanf("%d%d",&l,&r);
	if((sum<l*n)||(sum>r*n)){printf("-1\n");return 0;}
	int sum1=0,sum2=0;
	for(int i=1;i<=n;i++){
		if(a[i]>r)sum1+=(a[i]-r);
		if(a[i]<l)sum2+=(l-a[i]);
	}
	printf("%d\n",max(sum1,sum2));
	return 0;
}