n,m=map(int,input().split())
mod=998244353
memo=dict()
def dp(m,f):
    if m==0:return f
    if (m,f) in memo:return memo[m,f]
    ans=0
    for bx in range(2): #一番下の桁がbx
        next_f=f
        if next_f==1 and m%2==0 and bx==1:next_f=0
        if next_f==0 and m%2==1 and bx==0:next_f=1
        ans+=dp(m//2,next_f)*pow(n,bx,mod)
        ans%=mod
    memo[m,f]=ans
    return ans
print(dp(m,1))