N,K = map(int, input().split())
mod = 998244353

#コンビネーション
def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod

g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル

for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod )


if K==0:
    print(1)
    exit()
if K==1 and N%2==0:
    print(2)
    exit()
if K==1 and N%2==1:
    print(N-2)
    exit()
ans = 0
temp = ((N-K)//2)*2+1
for i in range(0,temp,2):
    ans = (ans + (i+1)*cmb(N-2-i,K-2,mod))%mod

print(ans)