NZEC Error in Python ATM Problem

I’ve written and solved this problem in c++ and i’m taking a stab at leaning python for bioinformatics. I keep getting NZEC error. I’ve tried placing the code in a function and returning 0. That still didn’t work and I also know that python doesn’t need to return 0. So the only other option is that it’s throwing some kind of error. Here is the code

withdrawal = float(input())
balance = float(input())

while balance > 0:
if (withdrawal + 0.50) > balance:
print("%.6f" % balance)
break
elif withdrawal % 5 != 0:
print("%.6f" % balance)
break
elif withdrawal % 5 == 0:
balance = balance - withdrawal - 0.50
print("%.6f" % balance)
break

or the link http://www.codechef.com/viewsolution/3926418

This website is so stupid. You have to take a whole string like stuff = raw_input(), then use stuff.strip() to get two elements. Then use int(stuff[0]) as your withdraw amount, and float(stuff[1]) as your balance. I hate this website. Just use their problems and solve them by yourself, but don’t submit your answer. Otherwise you may be very frustrated.