import sys
input = sys.stdin.readline
from collections import *

MOD = 998244353

N = int(input())
M = int(input())

if N<M:
    print(0)
    exit()
    
ans = pow(2, N, MOD)
sub = 1

for i in range(M):
    ans -= sub
    ans %= MOD
    sub *= N-i
    sub %= MOD
    sub *= pow(i, MOD-2, MOD)
    sub %= MOD

print(ans)