N,K = map(int,input().split())
import sys

P = 998244353

C = N + 5
fact = [1] * C
fact_inv = [1] * C
for i in range(2,C):
    fact[i] = fact[i-1] * i % P
fact_inv[-1] = pow(fact[-1],P-2,P)
for i in range(C-2,0,-1):
    fact_inv[i] = fact_inv[i+1] * (i + 1) % P
def comb(a,b):
    return fact[a] * fact_inv[b] * fact_inv[a-b] % P

if K == 0:
    print(1)
    exit()
if K == 1:
    if (N-1) % 2 == 1:
        print(2)
    else:
        print(N-2)
    exit()

ans = comb(N-2,N-K)
for i in range(1,(N-K)//2+1):
    ans = (ans + 2 * comb(N-2*i-2,K-2)) % P
    ans = (ans + comb(N-2*i-2,K-2) * (2*i-1))%P
print(ans)