n, d = gets.split.map(&:to_i)
a = Array.new(n, "o")
a[0] = "x"
count = 0
ind = d
n.times do
  if a[d] == "o"
    a[d] = "x"
    count += 1
    d = (d + ind) % n
  else
    puts count
    break
  end
end