class Integer
  def mod_inverse(mod)
    self.pow(mod - 2, mod)
  end
end

N = gets.to_i
M = gets.to_i
MOD = 998_244_353

a = 1
b = 1
sum = 1
all = 2.pow(N, MOD)

1.upto(M - 1) do |m|
  a = a * (N - m + 1) % MOD
  b = b * m % MOD
  sum += a * b.mod_inverse(MOD)
  sum %= MOD
end

puts (all - sum) % MOD