n,l=map(int,input().split())
if n<=l:
    print("1")
    exit()
def pow_r(x, n):
    if n == 0:  # exit case
        return 1
    if n % 2 == 0:  # standard case ① n is even
        return pow_r(x ** 2, n // 2)%998244353
    else:  # standard case ② n is odd
        return (x * pow_r(x ** 2, (n - 1) // 2))%998244353
ans=pow_r(2,n-l+1)%998244353
if ans>=1:
    print(ans-1)
else:
    print("998244352")