Trying to solve MIT OCW Pset 1.C. I don't get the desired output

Question

I was trying to solve the MIT OpenCourseWare Problem Set 1 C and I can't figure out why I'm not getting the output I require. The code is based on bisection search and it needs me to find the percentage of salary to save every month. Can someone help me understand where I'm going wrong?

Link to the question set

r = 0.04
current_savings = 0.0
annual_salary = float(input('Enter your Annual Salary: '))
total_cost = 1000000
semi_annual_raise = 0.07
portion_down_payment = 0.25 * total_cost
months = 0

counter = 0
epsilon = 100
low = 0
high = 1
guess = (high + low) / 2.0


def calc(test):
    months = 0
    current_savings = 0
    global portion_down_payment
    global annual_salary
    global semi_annual_raise
    global r
    while current_savings < portion_down_payment:
        if months % 6 == 0 and months != 0:
            annual_salary += annual_salary * semi_annual_raise
        current_savings += (current_savings * r / 12)
        current_savings += ((annual_salary / 12) * test / 1)
        months += 1
        if months > 36:
            break
    return current_savings


while abs(current_savings - portion_down_payment) >= epsilon:
    current_savings = calc(guess)
    counter += 1
    if calc(guess) < portion_down_payment:
        low = guess
    else:
        high = guess
    guess = guess = (high + low) / 2.0

print(guess, counter)

Input

150000

Expected Output

0.441, 12

Output received

1.4349296274686127e-42 138