I submitted my program to 1079 and get AC.
It at least shows that my ALGO work for small data.

By the way, my answer for 10^18 is
2504730781961
Is it right?

Maybe the 'int64' or some problems like this make me WA.
Could you please tell me why? I am confused.

Thanks in advance.

Well, sorry to ADMIN.
I have found my mistake and now I have AC.

BTW, my answer for 10^18 is correct.