如何获取symfony2中几个日期之间的天数并将值返回到数组

I'm trying to calculate number of days between few dates in my entity Symfony2. I have the entity with getDateFrom() and getDateTo(), which return DateTime. I write function :

public function getCountDays()
{

$total = array();

    foreach($this->getHolidays()  as $day)
    {
    $total[] =  (new DateTime($day->getDateTo()->format('Y-m-d')))->diff(new DateTime($day->getDateFrom()->format('Y-m-d')))->format('%a')+1 ;
    $sum =  array_sum($total);
    //print_r( $sum ) ;

    }

    return $sum;
}

Everything works, but this is not what I need. Function returns result "3567" (between the first dates: period is 3 days, between second dates: period is 2 days, and between third dates: period is 1 day and between fourth dates period is 1 day). Calculation is good, but I need only return 7. Any Ideas?

I found the solution, the problem was easy to solve. Array_sum must be after foreach loop like below.

public function getCountDays()
{

$total = array();

foreach($this->getHolidays()  as $day)
{
$total[] =  (new DateTime($day->getDateTo()->format('Y-m-d')))->diff(new DateTime($day->getDateFrom()->format('Y-m-d')))->format('%a')+1 ;


}


$sum =  array_sum($total);

return $sum;
}

Thanx for help.