#include<iostream>
#include<cstdio>

using namespace std;

const int maxn=55;

int n,sum,ansmore,ansless;
int fr,to;
int a[maxn];

int main()
{
	freopen("groupa.in","r",stdin);
	freopen("groupa.out","w",stdout);
	scanf("%d",&n);
	for(register int i=1;i<=n;i++) scanf("%d",a+i),sum+=a[i];
	scanf("%d%d",&fr,&to);
	if(sum<fr*n||sum>to*n) 
	{
		printf("-1\n");
		return 0;
	}
	for(register int i=1;i<=n;i++)
	{
		if(a[i]>to) ansmore+=(a[i]-to);
		else if(a[i]<fr) ansless+=(fr-a[i]);
	}
	printf("%d\n",ansmore>ansless?ansmore:ansless);
	return 0;
}