Ashish and Binary Matrix
/

Problem
Editorial
Analytics

Pulkit is really good at maths. Recently, he came to know about a problem on matrices. Amazed by the problem he got, he asked Ashish the same problem. Ashish also being good at maths solved the problem within 5 minutes. Now, its your time to solve the problem.

You will be given n*m binary matrix. You need to tell if it is possible to delete a column such that after deleting that column, rows of the matrix will be unique. If yes than print "Yes" else print "No".

[Input]
First line contains an integer t denoting no.of test cases.
Next line contains 2 integers n and m denoting no.of rows and columns.
Next n line contains binary string of length m each.

[Output]
For each test case output "Yes" or "No".

[Constraints]
1<=t<=100
1<=n<=1000
2<=m<=1000

SAMPLE INPUT
2
3 3
101
000
100
2 2
11
11
SAMPLE OUTPUT
Yes
No
Time Limit: 2.0 sec(s) for each input file.
Memory Limit: 256 MB
Source Limit: 1024 KB

## This Problem was Asked in

Initializing Code Editor...