import sys
input=lambda:sys.stdin.readline().rstrip()
mod=998244353
N,L=map(int,input().split())
time=(N+L-1)//L
ans=1
temp=2
while time:
	if time%2:
		ans=(ans*temp)%mod
	temp=(temp*temp)%mod
	time//=2
print((ans+mod-1)%mod)