mod = 998244353
N = int(input())
M = int(input())
X = int(0)

def factorial(n):
    Y = int(1)
    for _ in range(1,n+1):
        Y = Y*_
    return Y


def cmb(n,r):
    if n == 0:
        return 0
    if n<r:
        return "error"
    else:
        return int(factorial(n)/(factorial(r)*factorial(n-r)))


for _ in range(0,N-M+1):
    X += cmb(N,M+_)%mod

print(X%mod)