N = gets.to_i
X = gets.to_i
A = gets.to_i
B = gets.to_i

def f
  ng = 0
  ok = X

  while (ok - ng).abs >= 2
    v = (ok + ng) / 2

    if v * A >= X
      ok = v
    else
      ng = v
    end
  end

  ok
end

def g
  ng = 0
  ok = X
  lim = 2.pow(N - 1) - 1

  while (ok - ng).abs >= 2
    v = (ok + ng) / 2

    if X + v * B > lim
      ok = v
    else
      ng = v
    end
  end

  ok
end

puts [f, g].min