sub months {
    my (undef,undef,undef,$day,$month,$year) = localtime;
    $_[0] =~ m#^(\d+)/(\d+)/(\d+)$#;
    (12 * (1900 + $year - $1)) + 1 + $month - $2 - ($day < $3);
}
print months( "1999/06/30" ),$/;
print months( "2004/01/24" ),$/;
print months( "2004/01/25" ),$/;
__END__
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