var TEST = function () {
    
    function _recursionAdd(rtnNode, l1, l2) {
        if (l1) {
            rtnNode.val += l1.val;
            l1 = l1.next;
        }
        if (l2) {
            rtnNode.val += l2.val;
            l2 = l2.next;
        }
        
        if (rtnNode.val >= 10) {
            rtnNode.val -= 10;
            rtnNode.next = _recursionAdd(new ListNode(1), l1, l2);
        } else if  (l1 && l2) {
            rtnNode.next = _recursionAdd(new ListNode(0), l1, l2);
        } else {
            if (l1) {
                rtnNode.next = l1;
            } else if (l2) {
                rtnNode.next = l2;
            }
        }
        return rtnNode;
    }
    
    return {
        exec: function (l1, l2) {
            return _recursionAdd(new ListNode(0), l1, l2);
        }
    };
}();

var addTwoNumbers = function(l1, l2) {
    return TEST.exec(l1, l2);
};