local mfl, mce = math.floor, math.ceil
local mmi, mma = math.min, math.max
n, k = io.read("*n", "*n")
if k % 2 == 0 then
  if n % 2 == 0 then
    p1 = mfl(n / 2)
    p2 = k + 1
    print(mmi(p1, p2))
  else
    z = mfl(n / 2)
    if z <= mfl(k / 2) then
      print(n)
    else
      print(k + 1)
    end
  end
else
  hk = mfl(k / 2)
  if n % 2 == 0 then
    p1 = mfl(n / 2)
    p2 = (hk + 1) * 2
    print(mmi(p1, p2))
  else
    hn = mfl(n / 2)
    p1 = mmi(hk + 1, hn)
    p2 = mmi(hk + 1, hn + 1)
    print(mmi(p1 + p2, n))
  end
end