Write a function getDays that takes as parameters the month and the year. The function should then return the number of days in that month. If the use enters a number that is outside the valid range, then it must return $-1.$

Use the following criteria to identify leap years:

Determine whether the year is divisible by $100.$

If it is$,$ then it is a leap year if and only if it is divisible by $400.$ For example, $2000$ is a leap year but $2100$ is not.

If the year is not divisible by $100,$ then it is a leap year if and if only it is divisible by $4.$ For example, $2008$ is a leap year but $2009$ is not.