N = int(input())
M = int(input())
if N < M:
  print(0)
  exit()
if N == M:
  print(1)
  exit()
mod = 998244353

N %= mod
base = pow(2, N, mod)
val = 0
fact = 1
inv = 1
for i in range(M):
  val += fact * pow(inv, mod - 2, mod) % mod
  fact = fact * (N - i) % mod
  inv = inv * (i + 1) % mod
print((base - val) % mod)