Welcome to Enigmatico's bank! We offer a special program for your savings!

Since the first month you bring us your money, each month that passes your money reevaluates each month, following the following formula:

+ * (1/4)t^3-(109/50)t^2+3t

Where t is the time in months since your first deposit. However, you must keep your money for a minimum of 5 months. Will you take it? If so, when do you withdraw your money?