mod=998244353
def cmb(n,r):
  if r<0 or r>n:
    return 0
  return ((g1[n]*g2[r]%mod)*g2[n-r])%mod
 
N=1000000
g1=[1]*(N+3)
for i in range(2,N+3):
  g1[i]=g1[i-1]*i%mod
g2=[0]*len(g1)
g2[-1]=pow(g1[-1],mod-2,mod)
for i in range(N+1,-1,-1):
  g2[i]=g2[i+1]*(i+1)%mod
inv=[0]*(N+3)
for i in range(1,N+3):
  inv[i]=g2[i]*g1[i-1]%mod
N,K=map(int,input().split())
if K==0:
  print(1)
  exit()
if K==1:
  if N&1:
    print(N-2)
  else:
    print(2)
  exit()
if N==K:
  print(1)
  exit()
if K==2:
  N>>=1
  print(N*N%mod)
  exit()
A,B=0,0
x,y=1,2
for i in range(2,N+1):
  if i&1:
    x+=y
    if x>=mod:
      x-=mod
    y+=1
  A=(A+x*cmb(N-2-i,K-3))%mod
for i in range(3,K+1):
  A=(A+cmb(N-1-i,K-i))%mod
x,y=1,2
N-=2
for i in range(2,N+1):
  if i&1:
    x+=y
    if x>=mod:
      x-=mod
    y+=1
  B=(B+x*cmb(N-2-i,K-3))%mod
for i in range(3,K+1):
  B=(B+cmb(N-1-i,K-i))%mod
print((A+B)%mod)