<?php
$a[] = '56';
$a[] = '66';
$a[] = '';
$a[] = '58';
$a[] = '85';
$a[] = '';
$a[] = '';
$a[] = '76';
$a[] = '';
$a[] = '57';
// $a[] = 0;
echo $average;
PD9waHAKJGFbXSA9ICc1Nic7CiRhW10gPSAnNjYnOwokYVtdID0gJyc7CiRhW10gPSAnNTgnOwokYVtdID0gJzg1JzsKJGFbXSA9ICcnOwokYVtdID0gJyc7CiRhW10gPSAnNzYnOwokYVtdID0gJyc7CiRhW10gPSAnNTcnOwovLyAkYVtdID0gMDsKJGEgPSBhcnJheV9maWx0ZXIoJGEpOwokYXZlcmFnZSA9IGFycmF5X3N1bSgkYSkvY291bnQoJGEpOwplY2hvICRhdmVyYWdlOw==