<?php
    class Node {
        public $leaf;
        public $kids = array();

        function __construct($leaf) {
            $this->leaf = $leaf;
        }

        function childExists($childVal) {
            return (array_key_exists($childVal, $this->kids));
        }

        function addChild($childVal, $isLeaf) {
            $newNode = new Node($isLeaf);
            $this->kids[$childVal] = $newNode;
            return $this->kids[$childVal];
        }

        function getChild($childVal) {
            return $this->kids[$childVal];
        }

        function hasChilds() {
            return (!empty($this->kids));
        }

        function checkLeaf() {
            return $this->leaf;
        }
    }

    fscanf(STDIN, "%d", $numOfTestCases);

    for ($i = 0; $i < $numOfTestCases; $i++) { //Loop for reading test cases
        fscanf(STDIN, "%d", $numOfPhoneNumbers);

        $isConsistent = true;
        $startNode = new Node(false);

        for ($j = 0; $j < $numOfPhoneNumbers; $j++) { //Loop for reading phone numbers of each test case
            fscanf(STDIN, "%d", $newNumber);

            if ($isConsistent) { // Does not need to check new number if list is already inconsistent
                $numArr = str_split(strval($newNumber)); // Spitting new number into array
                $currNode = $startNode;
                $isConsistent = true;

                foreach ($numArr as $k => $numstr) { // Loop for checking each digit
                    if ($currNode->checkLeaf()) { // If current node is a leaf
                        $isConsistent = false;
                        break;
                    } else {
                        if (!$currNode->childExists($numstr)) {
                            if ($k == count($numArr)-1) {
                                $currNode = $currNode->addChild($numstr, true);
                            } else {
                                $currNode = $currNode->addChild($numstr, false);
                            }
                        } else {
                            $currNode = $currNode->getChild($numstr);
                        }
                    }
                }

                if ($currNode->hasChilds()) $isConsistent = false;
            }
        }

        $newAnswer = ($isConsistent) ? "YES" : "NO";
        $ansString = ($i == 0) ? $newAnswer : $ansString."\n".$newAnswer;
    }

    fwrite(STDOUT, $ansString);

    exit(0);
?>