github.com/captn3m0/codechef.git

---
languages_supported:
    - NA
title: N3
category: NA
old_version: true
problem_code: N3
tags:
    - NA
layout: problem
---
###  All submissions for this problem are available. 

You are given a set of N strings S0, S1, …, SN-1. These strings consist of only lower case characters a..z and have the same length L.

A string H is said to be K-important if there are at least K strings in the given set of N strings appearing at K different positions in H. These K strings need not to be distinct.

Your task is to find the shortest K-important string. If there are more than one possible solution, your program can output any of them.

### Input

The first line contains a number t (about 10) which is the number of test cases.

Each test case has the following form.

The first line contains three integers N, L and K. The next N lines contain the strings in the given set.

Each test case's input is separated by a blank line.

### Constraints

- 1 ≤ N ≤ 150
- 1 ≤ L ≤ 300
- 1 ≤ K ≤ 500

### Output

For each test case, output the following information.

The first line contains the length of the shortest K-important strings.

The second line contains H, one of the K-important strings.

Each line in the next K lines contains the index of one string in the given set that appears in H and the corresponding position (0-based) in H.

Print a blank line after each test case's output.

### Example

<pre>
<b>Input</b>
3

3 3 1
abc
cde
bcf

3 3 2
abc
cde
bcf

3 3 3
abc
cde
bcf

<b>Output</b>
3
abc
0 0

4
abcf
0 0
2 1

7
abcfabc
0 0
2 1
0 4
</pre>