monthlyPayment = 10
balance = 900
annualInterestRate = .2
testBalance = balance

while testBalance >= 0:
    for month in range(1,13):
        testBalance = (testBalance - (monthlyPayment)*(1+(annualInterestRate/12)))
    if testBalance >= 0:
        testBalance = balance
    monthlyPayment += 10

print('Lowest Payment: ' + str(monthlyPayment))