balance = 320000
annualInterestRate = 0.20

monthlyInterestRate = annualInterestRate / 12
MonthlyPaymentLowerBound = balance / 12
MonthlyPaymentUpperBound = balance * ((1 + monthlyInterestRate)**12 / 12)
balance2=balance
ans=round((MonthlyPaymentLowerBound + MonthlyPaymentUpperBound) / 2.0+0.01, 8)

while True:


    for month in range(12):
        balance2=balance2-ans
        balance2=balance2 + balance2 * monthlyInterestRate
    if abs(balance2) < 0.08:
        break;

    if balance2 > 0:
        MonthlyPaymentLowerBound=ans
    elif balance2 < 0:
        MonthlyPaymentUpperBound=ans

    ans=round((MonthlyPaymentUpperBound+MonthlyPaymentLowerBound)/ 2.0+0.01,8)
    balance2=balance

print('Lowest payment: ' + str(round(ans,2)))