ATM , Python Runtime Error ! Nzec

general
, ,
1

balance=int(raw_input())
while True:
withdraw=int(raw_input())

if withdraw <= 2000 and withdraw%5==0 and balance<=2000:
    if withdraw<balance:
        balance=(balance-(withdraw+0.50))
        print "%.2f" % balance
    else:
        print "%.2f" % balance
else:
    break

What is going wrong in my code?

2 
withdraw=input()
balance=input()
if **balance>withdraw+0.5** and withdraw%5==0:
        print balance*(1.0)-(withdraw+0.5)    // multiplied with 1.0 to make float
else:
        print balance