Input field should not allow the user to enter more than 5 values
Search for maxlength attribute here:
http://www.html5rocks.com/en/tutorials/forms/html5forms/
User should not allow to type more than 5 numbers
Maybe you can try to put a directive in the input div watching the input length,
$scope.$watch();
then blur user from the input when the length equals or greater than 5.