Laravel 5.1 PHPexcel install error

I want to add class PHPExcel to my project. I use composer to add PHPExcel. I tried some command line.

php composer.phar update

or

php composer.phar require phpexcel/phpexcel

But, i alway receive error look like image: at here. And maatwebsite/excel, too.

What is wrong with my project? Please help me!

via Chebli Mohamed