Write a program that reads several matrices of integer numbers, and that for each one tells whether the result of traversing it in zig-zags is a strictly increasing sequence. We must start at the top-left position, go down the first column, up the second column, down the third column, and so on.

**Input**

Input consists of several matrices,
each with the number of rows *r* ≥ 1
and the number of columns *c* ≥ 1,
followed by *r* rows with *c* integer numbers each.

**Output**

For every matrix,
print its number followed by either “`yes`” o “`no`”,
depending on whether the zig-zag traversal of the matrix
generates a strictly increasing sequence or not.

Public test cases

**Input**

3 4 10 15 36 41 11 14 37 40 12 13 38 39 3 2 10 11 12 13 14 15 2 2 5 7 6 6 2 3 1 4 5 2 3 5 1 1 -3 1 3 4 6 8 2 1 100 200

**Output**

matriu 1: yes matriu 2: no matriu 3: no matriu 4: no matriu 5: yes matriu 6: yes matriu 7: yes

Information

- Author
- Professors de P1
- Language
- English
- Translator
- Salvador Roura
- Original language
- Catalan
- Other languages
- Catalan
- Official solutions
- C++
- User solutions
- C++