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