# chatGPT
import sys

MOD = 998244353

def comb_large_n(n, r):
    if r < 0 or r > n:
        return 0
    num = 1
    den = 1
    for i in range(r):
        num = num * (n - i) % MOD
        den = den * (i + 1) % MOD
    return num * pow(den, MOD - 2, MOD) % MOD


def main():
    N, M = map(int, sys.stdin.readline().split())

    A = (pow(2, N, MOD) - 1) % MOD
    B = (pow(2, N - 1, MOD) - 1) % MOD

    total = comb_large_n(A, M)
    bad = A * comb_large_n(B, M - 1) % MOD

    ans = (total - bad) % MOD

    print(ans)


if __name__ == "__main__":
    main()