Help with problem

I need to write a program to calculate the minimum payment per month for an initial balance. The balance accrues interest each month at a set rate. The first month should not have any interest. The minimum payment needs to be in increments of 10. I got this so far, but the answer is coming up over by 10. I got 370 and it should be 360. Any help will be appreciated.

month = 1
balance = 3926
annualInterestRate = 0.2
payment = 0

while balance >= 0:
    remainingBalance = balance - payment
    while month < 12:
        monthlyInterest = (annualInterestRate) / 12
        remainingBalance = (remainingBalance - payment) * (1 + monthlyInterest)
        month +=1
    if month == 12:
        payment += 10
    if remainingBalance <= 0:
        break
    month = 1
    
print "Lowest Payment: " + str(payment)