import sys

N,A,B,X,Y = list(map(int,input().split()))
H = list(map(int,input().split()))
h = sorted(H,reverse = True)

def check(K):
    l = [max(0,i-K) for i in h]
    count = 0
    i = 0
    while count < A and i < N:
        q = l[i] // X
        if q == 0:break
        q = min(A - count,q)
        count += q
        l[i] -= q * X
        i += 1
    if count < A:
        l.sort(reverse = True)
        for i in range(min(A-count,len(l))):
            l[i] = 0
    return sum(l) <= B * Y

if check(0):
    print(0)
    exit()
start = 0
end = 10 ** 9
while start != end:
    mid = end - (end - start + 1) // 2
    if check(mid):
        end = mid
    else:
        start = mid + 1
print(start)