Kilani and Abd are neighbors for 3000 years, but then the day came and Kilani decided to move to another house. As a farewell gift, Kilani is going to challenge Abd with a problem written by their other neighbor with the same name Abd.

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The problem is:

You are given a connected tree rooted at node $$$1$$$.

You should assign a character a or b to every node in the tree so that the total number of a's is equal to $$$x$$$ and the total number of b's is equal to $$$n - x$$$.

Let's define a string for each node $$$v$$$ of the tree as follows:

if $$$v$$$ is root then the string is just one character assigned to $$$v$$$:
otherwise, let's take a string defined for the $$$v$$$'s parent $$$p_v$$$ and add to the end of it a character assigned to $$$v$$$.

You should assign every node a character in a way that minimizes the number of distinct strings among the strings of all nodes.

Input

The first line contains two integers $$$n$$$ and $$$x$$$ ($$$1 \leq n \leq 10^5$$$; $$$0 \leq x \leq n$$$) — the number of vertices in the tree the number of a's.

The second line contains $$$n - 1$$$ integers $$$p_2, p_3, \dots, p_{n}$$$ ($$$1 \leq p_i \leq n$$$; $$$p_i \neq i$$$), where $$$p_i$$$ is the parent of node $$$i$$$.

It is guaranteed that the input describes a connected tree.

Output

In the first line, print the minimum possible total number of distinct strings.

In the second line, print $$$n$$$ characters, where all characters are either a or b and the $$$i$$$-th character is the character assigned to the $$$i$$$-th node.

Make sure that the total number of a's is equal to $$$x$$$ and the total number of b's is equal to $$$n - x$$$.

If there is more than one answer you can print any of them.

Note

The tree from the sample is shown below:

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The tree after assigning characters to every node (according to the output) is the following:

$\text{[math]}$

Strings for all nodes are the following:

string of node $$$1$$$ is: a
string of node $$$2$$$ is: aa
string of node $$$3$$$ is: aab
string of node $$$4$$$ is: aab
string of node $$$5$$$ is: aabb
string of node $$$6$$$ is: aabb
string of node $$$7$$$ is: aabb
string of node $$$8$$$ is: aabb
string of node $$$9$$$ is: aa

The set of unique strings is $$$\{\text{a}, \text{aa}, \text{aab}, \text{aabb}\}$$$, so the number of distinct strings is $$$4$$$.

AB Tree

Examples