N, M, P = gets.split.map(&:to_i)
A = gets.split.map(&:to_i)
AM = A.max

values = Array.new(Math.log2(M).ceil + 10, 0)

A.each do |a|
  cost = 1
  e = a

  while e % P == 0
    e /= P
    cost += 1
  end

  next if e == 1

  if values[cost] < e
    values[cost] = e
  end
end

L = Math.log2(M).ceil ** 2 + 10
dp = Array.new(L + 1, 0)
dp[0] = 1

values.each.with_index do |e, cost|
  next if e == 0

  0.upto(L) do |i|
    next if dp[i] == 0
    next if dp[i] > M

    nv = i + cost
    x = dp[i] * e

    if dp[nv] < x
      dp[nv] = x
    end
  end
end

0.upto(L) do |cost|
  if dp[cost] * AM > M
    puts cost + 1
    exit
  end
end

puts -1