I was recently wondering what complexity loop can be used in less than 1 sec. For the same, I took one of my previously solved problems and added an extra loop but, even after I increase the looping to as high as 10^15, I get Accepted within 15ms. How could this happen?

Attached is a screenshot of my solution which includes a 10^15 loop which gets accepted within 15ms.

Problem link: http://codeforces.net/problemset/problem/371/C

Solution link: https://paste.ofcode.org/37dpgTeNtDQSt4uU5BEWiLa

PS: If this a bad place to ask for this query, please let me know where to post this. :)