Kid was gifted a tree of n vertices with the root in the vertex 1 . Since he really like symmetrical objects, Kid wants to find out if this tree is symmetrical. Formally, a tree is symmetrical if there exists an order of children such that: The first line of input data contains single integer t ( 1 <= t <= 10^4 ) -- the number of test cases in the test. The first line of each case contains an integer n ( 1 <= n <= 2 cdot 10^5 ) -- the number of vertices in the tree. The following n-1 lines contain two integers each u and v ( 1 <= u, v <= n , u neq v ) -- indices of vertices connected by an edge. It is guaranteed that the sum of n over all cases does not exceed 2 cdot 10^5 . Output t strings, each of which is the answer to the corresponding test case. As an answer, output "YES" if this tree is symmetrical, and "NO" otherwise. You can output the answer in any case (for example, the strings "yEs", "yes", "Yes" and "YES" will be recognized as a positive answer).