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my $a = 0;my $b = 0;my $c = 1;print "true1\n" if $a and $b or $c;print "true2\n" if $a and ($b or $c);print "true3\n" if ($a and $b) or $c;print "true4\n" if $a and $b || $c;print "true5\n" if ($a and $b) || $c;