var TEST = function () {
    
    function _getNum(node) {
        let str = '';
        while (node && node !== 0) {
            str = node.val + str;
            node = node.next;
        }
        return parseInt(str) || 0;
    }
    
    function _getNode(str) {
        let node = 0;
        let len = str.length;
        for (var i=0; i<len; ++i) {
            node = new ListNode(str[i], node);
        }
        return node;
        
    }

    return {
        exec: function (l1, l2) {
            return _getNode(_getNum(l1) + _getNum(l2) + '');
        }
    };
}();