N,M=map(int,input().split())
P=998244353
a=1
M=min(N-M,M)
E=[1,789885751,432351202,310769109,77784134,24770542,856452172,292795459,310328833,229885020,910573117,541537097,592483685,475099103,428301920,351370758,170926160,222785194,239754689,687751559,245280646,706029275,280382318,11880047,271673172,495968583,634671016,583177582,103128368,42384375,712333871,845347712,22818060,254478574,972918293,169555925,936514026,747662027,830659092,307107320,474733431,898568348,941552927,611036992,598990751,789475199,374801082,439339251,42074518,909045292,548833449,309380768,333105486,193503119,383628463,48496927,321709079,362476217,854866728,402662299]
def f(i):
	i%=P;t=E[i>>24]
	for j in range(((i>>24)<<24)+1,i+1):t=t*j%P
	return t
if M:a=0if N-M<P<=N else f(N)*pow(f(M)*f(N-M),-1,P)%P
print(a)