* $1 ≤ N ≤ 100.000$
* $1 ≤ M ≤ 400.000$
* $1 ≤ a{~i~}, b{~i~} ≤ N$

* $a{~i~} ≠ b{~i~}$

* $1 a{~i~} ≠ b{~i~}$

* $Cele M perechi reprezinta toate perechile posibile din puzzle. Daca puzzle-ul are R randuri si C coloane atunci M = (R - 1) * C + (C - 1) * R$
* $Se garanteaza existenta unei solutii.$
* $Se accepta orice solutie corecta.$

3 2
6 2
| 3 3

4 5 6
7 3 2
1 9 8

2 4 8
3 5 9
6 7 1

|
== include(page="template/taskfooter" task_id="puzzle2") ==