Wrong ansewer!!!

can any 1 explain me what is the problem with my code

https://www.codechef.com/viewsolution/15219242 after submitting its showing wrong answer.plz help.!!

Account should have enough money for Withdrawl+Bank charges. You are only checking for withdrawl. Include bank charges of 0.5 in it as well.

Eg, for input 120 120 , make sure you arent printing -0.5