if (($a == 3) || ($a ==  77) || ($a == 8))
-- is equivalent to --
if (($a != 3) && ($a !=  77) && ($a != 8))

##</code><code>##

if (($a == 3) || ($a ==  77) || ($a == 8))
-- is equivalent to --
if (!( ($a != 3) && ($a !=  77) && ($a != 8) ))