=IF($D$3>=28
,DATE(YEAR($B$3),MONTH($B$3)+1,0)
,IF(DAY($B$3)<=$D$3
,DATE(YEAR($B$3),MONTH($B$3),$D$3)
,DATE(YEAR($B$3),MONTH($B$3)+1,$D$3)
)
)
=IF(DAY(DATE(YEAR($F$4),MONTH($F$4)-1,DAY($F$4))+1)>$D$3
,DATE(YEAR($F$4),MONTH($F$4)-1,DAY($F$4))+1
,DATE(YEAR($B$3),MONTH($B$3),1)
)