我的代码不能在python空闲时运行

Question

我应该写一个代码来支付一年或更少的信用卡债务，其中余额和年利率是投入，产出是每月分期偿还一年或更少的债务。剩下的上限和下限所需的数学在代码中。请帮助。

balance = int(raw_input())
annualInterestRate = float(raw_input())


lowestPayment = balance
monthlyPayment = 0
monthlyUnpaid = 0
temp = balance
monthlyInterest = 0

lowerBound = balance/12
upperBound = balance*((1+annualInterestRate/12.0)**12)/12.0
mid = 0

while  upperBound - lowerBound > 0.0000:
    mid = (upperBound + lowerBound)/2.0
    monthlyPayment = mid
    balance = temp
    for i in range(1,13):
        monthlyUnpaid = balance - monthlyPayment
        monthlyInterest = annualInterestRate/12.0 * monthlyUnpaid
        balance = monthlyUnpaid + monthlyInterest
    if int(balance) <= 0:
        upperBound = mid - 1
        if monthlyPayment < lowestPayment:
            lowestPayment = monthlyPayment
    elif int(balance) > 0:
        lowerBound = mid + 1


print 'Lowest Payment: '+str(round(lowestPayment,2))