mine))

gotcha.

...because that would have been an incorrect formula.

Test failed with month = 1: 0 should equal 1
Test failed with month = 7: 2 should equal 3
Test Passed
Test Passed
Test Passed
Test failed with month = 4: 1 should equal 2
Test failed with month = 2: 0 should equal 1
Test failed with month = 10: 3 should equal 4
Test failed with month = 11: 3 should equal 4
Test failed with month = 8: 2 should equal 3
Test Passed
Test failed with month = 5: 1 should equal 2

Already reported in kangacoyote's post below.

Not sure the language you're coding in, but testing this in Python:

Those are not the duplicates you are looking for.: [1, 3, 4] should equal [4, 3, 1]