import sys
input=lambda:sys.stdin.readline().rstrip()
mod=998244353
N,K=map(int,input().split())
def p(a,b):
	temp=a
	ans=1
	while b>0:
		if b%2:
			ans=(ans*temp)%mod
		b//=2
		temp=(temp*temp)%mod
	return ans
C=1
ans=0
for l in range(N):
	ans=(ans+C*p(l,K))%mod
	C=C*(N-1-l)//(l+1)
print(ans)