Nested ng-repeat with checkboxes

I'm creating table with nested ng-repeat but checkboxes in each column have synchronous reaction when being checked/unchecked. How to fix this behaviour so each checkbox could be checked on its own?

HTML:

<tr ng-repeat="person in persons | orderBy: 'secondName'">
    <td>
        {{person.firstName + ' ' + person.secondName}}
    </td>
    <td ng-repeat="day in person.daysOfWeek">
        <input type="checkbox" 
        name="{{day.name}}" 
        ng-model='day.checked'/>
    </td>
</tr>

Code:

var daysOfWeek = [ { name: 'Sun', checked: '' }
                  ,{ name: 'Mon', checked: '' }
                  ,{ name: 'Tue', checked: '' }
                  ,{ name: 'Wen', checked: '' }
                  ,{ name: 'Thu', checked: '' }
                  ,{ name: 'Fri', checked: '' }
                  ,{ name: 'Sat', checked: ''}];
var persons = 
    [{ firstName: 'Jil', secondName: 'Mith' }
     ,{ firstName: 'Alvin', secondName: 'Zurb' }
     ,{ firstName: 'John', secondName: 'Burt' }
     ,{ firstName: 'Tom', secondName: 'Kurtz' }];

persons.forEach(function(person) {
    person.daysOfWeek = daysOfWeek;
});

angular.module('MyApp',[]);

function MyCtrl($scope) {
    $scope.persons = persons;
    console.log($scope.persons);

    $scope.saveInfo = function() {
        console.log($scope.persons);
    };
}

The Fiddle is here