N,L=map(int,input().split())
M=((N+L-1)//L) #枚の板を動かすのと同じ.
#2**M-1のmod 998244353を求めるM>=1
MOD=998244353
ans=1
p=2**1
i=0
while M>0:
    while M%2==0:
        p=(p*p)%MOD
        M=M//2
    
    ans=(ans*p)%MOD
    M-=1

print((ans+MOD-1)%MOD)