def main():
    from sys import stdin, setrecursionlimit
    # setrecursionlimit(1000000)
    input = stdin.readline
    def iinput(): return int(input())
    def sinput(): return input().rstrip()
    def i0input(): return int(input()) - 1
    def linput(): return list(input().split())
    def liinput(): return list(map(int, input().split()))
    def miinput(): return map(int, input().split())
    def li0input(): return list(map(lambda x: int(x) - 1, input().split()))
    def mi0input(): return map(lambda x: int(x) - 1, input().split())
    INF = 1000000000000000000
    MOD = 998244353

    N = iinput()
    M = iinput()

    if M > N:
        print(0)
        return

    def modinv(a):
        b = MOD
        u, v = 1, 0
        while b > 0:
            t = a // b
            a -= t * b
            a, b = b, a
            u -= t * v
            u, v = v, u
        return u % MOD

    ans = pow(2, N % (MOD - 1), MOD)
    tmp = 1
    for k in range(M):
        ans -= tmp
        ans %= MOD
        tmp *= N - k
        tmp %= MOD
        tmp *= modinv(k + 1)
        tmp %= MOD
    print(ans)

main()