gets.to_i.times{
  n,x=gets.split.map &:to_i
  ans=0
  n+=1
  if x%2==1
    ans+=n/2
  else
    t=x*(x+1)
    ans+=n/t*(x/2*(x+2))
    n%=t
    if n<=x
      ans+=n/2
    else
      n-=x
      ans+=x/2
      if n<=x
        ans+=(n+1)/2
      else
        n-=x
        ans+=x/2
        t=n/x
        ans+=2*t
        ans+=(x/2-2)*t
        ans+=(t+1)/2
        n%=x
        if n<=t+1
          if t%2==0
            ans+=(n+1)/2
          else
            ans+=n/2
          end
        else
          ans+=(t+2)/2
          n-=t+1
          ans+=(n+1)/2
        end
      end
    end
  end
  p ans%998244353
}