#include <fstream>

#define I_F "groupa.in"
#define O_F "groupa.out"
#define MAX 50

using namespace std;

short n;
long s[MAX];
long l,r,ans;

void Input();
void Search();
void Output();

int main()
{
	Input();
	Search();
	Output();
	return 0;
}

void Input()
{
	ifstream fin(I_F);
	fin>>n;
	for (short i=0; i<n; fin>>s[i++]);
	fin>>l>>r;
	fin.close();
}

void Search()
{
	short i;
	long long m=0;
	for (i=0; i<n; m+=s[i++]);
	if (((long long)n*(long long)l>m)||((long long)n*(long long)r<m))
		ans=-1;
	else
	{
		long t1=0,t2=0;
		for (i=0; i<n; i++)
			if (s[i]<l)
				t1+=(l-s[i]);
			else
				if (s[i]>r)
					t2+=(s[i]-r);
		if (t1>t2)
			ans=t1;
		else
			ans=t2;
	}
}

void Output()
{
	ofstream fout(O_F);
	fout<<ans<<'\n';
	fout.close();
}