{
:local arrDaysOnMonths {jan="31";feb="28";mar="31";apr="30";may="31";jun="30";jul="31";aug="31";sep="30";oct="31";nov="30";dec="31"}
:if ((([:pick [/system clock get date] 7 11] - 1968) % 4) = 0) do={:set ($arrDaysOnMonths->"feb") 29}
:put "Days on this month: $($arrDaysOnMonths->[:pick [/system clock get date] 0 3])"
}