import sys

MOD = 998244353

def main():
    N = int(sys.stdin.readline())
    M = int(sys.stdin.readline())
    
    if M > N:
        print(0)
        return
    
    mod = MOD
    b = N % mod
    t = min(M-1, b)
    
    sum_c = 0
    current = 1  # C(b, 0)
    sum_c = current % mod
    
    for k in range(1, t + 1):
        current = current * (b - k + 1) % mod
        current = current * pow(k, mod-2, mod) % mod
        sum_c = (sum_c + current) % mod
    
    pow_2n = pow(2, N, mod)
    ans = (pow_2n - sum_c) % mod
    if ans < 0:
        ans += mod
    print(ans)

if __name__ == "__main__":
    main()