balance = 999999
annualInterestRate = 0.18
monthly_interest_rate = annualInterestRate /12.0
lower_bound = balance / 12.0
upper_bound = (balance * (1 + monthly_interest_rate)**12) / 12.0

def calculate_balance(balance, fixed):
    month = 0
    while month < 12:
        balance = (balance - fixed) * (monthly_interest_rate + 1)
        month += 1
        balance
    return balance

while True:
    if abs(calculate_balance(balance, lower_bound) - balance) > 0.01:
        if calculate_balance(balance, lower_bound) > 0:
            mark = lower_bound
            lower_bound = (lower_bound + upper_bound) / 2
        elif calculate_balance(balance, lower_bound) < 0:
            upper_bound = lower_bound
            lower_bound = mark
    else:
        break
print(lower_bound)