#include <iostream>
#include <algorithm>
using namespace std;
int a[55];
int main()
{
    int n , b , c , sum , x , y , ans;
	cin >> n;
	for(int i = 1;i <= n;i++)
		cin >> a[i];
	cin >> x >> y;
    for(int i = 1;i <= n;i++)
        sum += a[i];
	if(sum < n * x || sum > n * y)
	{
		cout << "-1";
		return 0;
	}
	for(int i = 1;i <= n;i++)
	{
		if(a[i] < x)
			b += x - a[i];
		if(a[i] > y)
            c += a[i] - y;
	}
	cout << max (b , c);
    return 0;
}