B'You are given an unweighted tree with n vertices. Recall that a tree is a connected undirected graph without cycles. Your task is to choose three distinct vertices a, b, c on this tree such that the number of edges which belong to at least one of the simple paths between a and b , b and c , or a and c is the maximum possible. See the notes section for a better understanding. The simple path is the path that visits each vertex at most once. The first line contains one integer number n ( 3 <= n <= 2 cdot 10^5 ) -- the number of vertices in the tree. Next n - 1 lines describe the edges of the tree in form a_i, b_i ( 1 <= a_i , b_i <= n , a_i ne b_i ). It is guaranteed that given graph is a tree. In the first line print one integer res -- the maximum number of edges which belong to at least one of the simple paths between a and b , b and c , or a and c . In the second line print three integers a, b, c such that 1 <= a, b, c <= n and a ne, b ne c, a ne c . If there are several answers, you can print any. The picture corresponding to the first example (and another one correct answer): If you choose vertices 1, 5, 6 then the path between 1 and 5 consists of edges (1, 2), (2, 3), (3, 4), (4, 5) , the path between 1 and 6 consists of edges (1, 2), (2, 3), (3, 4), (4, 6) and the path between 5 and 6 consists of edges (4, 5), (4, 6) . The union of these paths is (1, 2), (2, 3), (3, 4), (4, 5), (4, 6) so the answer is 5 . It can be shown that there is no better answer. '...