n, l = gets.split.map(&:to_i)
D = 998244353

def pow2mod(n)
  raise 'must not happen' if n < 0
  return 1 if 0 == n
  p = pow2mod(n/2) ** 2
  p *= 2 if 1 == n%2
  p % D
end

n = (n.to_f / l).ceil
puts (pow2mod(n) - 1) % D