n,c0=map(int,input().split())
c1=n-c0
M=998244353
N=n
fa=[1]
for i in range(1,N+1):
  fa+=[fa[-1]*i%M]
fb=[pow(fa[N],M-2,M)]
for i in reversed(range(1,N+1)):
  fb+=[fb[-1]*i%M]
fb.reverse()
fc=lambda n,k:fa[n]*fb[k]*fb[n-k]%M if n>=k>=0 else 0
a=0
if c0>=2:
  for i in range(c1-2+1):
    if (c1-i)%2==0:
      a+=fc(c0-2+i,i)*(c1-i-1)
      a%=M
  for i in range(c1):
    if (c1-i)%2==0:
      a+=fc(c0-2+i,i)*2
      a%=M
  a+=fc(c0-2+c1,c1)
  a%=M
elif c0==1:
  for i in range(1,n-1):
    a+=(i)%2==(n-1-i)%2
  a+=((n-1)%2)*2
  a%=M
else:
  a=1
print(a)