Distance Matching

You are given an integer k and a tree T with n nodes (n is even).

Let dist(u, v) be the number of edges on the shortest path from node u to node v in T.

Let us define a undirected weighted complete graph G = (V, E) as following:

• V = \{x ∣ 1 ≤ x ≤ n } i.e. the set of integers from 1 to n
• E = {(u, v, w) ∣ 1 ≤ u, v ≤ n, u ≠ v, w = dist(u, v) } i.e. there is an edge between every pair of distinct nodes, the weight being the distance between their respective nodes in T

Your task is simple, find a perfect matching in G with total edge weight k (1 ≤ k ≤ n^2).

Input

The first line of input contains two integers n, k (2 ≤ n ≤ 100 000, n is even, 1 ≤ k ≤ n^2): number of nodes and the total edge weight of the perfect matching you need to find.

The i-th of the following n - 1 lines contains two integers v_i, u_i (1 ≤ v_i, u_i ≤ n) denoting an edge between v_i and u_i in T. It is guaranteed that the given graph is a tree.

Output

If there are no matchings that satisfy the above condition, output "NO" (without quotes) on a single line.

Otherwise, you should output "YES" (without quotes) on the first line of output.

You should then output n/2 lines, the i-th line containing p_i, q_i (1 ≤ p_i, q_i ≤ n): the i-th pair of the matching.

Examples

Input

4 2 1 2 2 3 3 4

Output

YES 2 1 3 4

Input

4 4 1 2 2 3 3 4

Output

YES 3 1 2 4

Note

A tree is a connected acyclic undirected graph.

A matching is set of pairwise non-adjacent edges, none of which are loops; that is, no two edges share a common vertex.

A perfect matching is a matching which matches all vertices of the graph; that is, every vertex of the graph is incident to exactly one edge of the matching.

inputFormat

Input

The first line of input contains two integers n, k (2 ≤ n ≤ 100 000, n is even, 1 ≤ k ≤ n^2): number of nodes and the total edge weight of the perfect matching you need to find.

The i-th of the following n - 1 lines contains two integers v_i, u_i (1 ≤ v_i, u_i ≤ n) denoting an edge between v_i and u_i in T. It is guaranteed that the given graph is a tree.

outputFormat

Output

If there are no matchings that satisfy the above condition, output "NO" (without quotes) on a single line.

Otherwise, you should output "YES" (without quotes) on the first line of output.

You should then output n/2 lines, the i-th line containing p_i, q_i (1 ≤ p_i, q_i ≤ n): the i-th pair of the matching.

Examples

Input

4 2 1 2 2 3 3 4

Output

YES 2 1 3 4

Input

4 4 1 2 2 3 3 4

Output

YES 3 1 2 4

Note

A tree is a connected acyclic undirected graph.

A matching is set of pairwise non-adjacent edges, none of which are loops; that is, no two edges share a common vertex.

A perfect matching is a matching which matches all vertices of the graph; that is, every vertex of the graph is incident to exactly one edge of the matching.

样例

4 2
1 2
2 3
3 4

YES
1 2
3 4

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