#include<cstdio>
#include<algorithm>

using namespace std;

int n,L,R,cl,cr,sum,ans;
int a[60];

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>n*R||sum<n*L){
		printf("-1");return 0;
	}
	for(int i=1;i<=n;i++){
		if(a[i]>R)cr+=a[i]-R;
		else if(a[i]<L)cl+=L-a[i];
	}
	printf("%d",max(cl,cr));
	return 0;
}