h2. Restricţii si precizari

* $0 ≤ M ≤ 100.000$

* $0 ≤ M ≤ 100 000$

* $1 ≤ val{~X~} ≤ 100.000$ ({$1 ≤ X ≤ N$})

* $1 ≤ val{~X~} ≤ 100 000$ ({$1 ≤ X ≤ N$})

* Seful suprem va avea seful direct codificat cu $-1$.

* Antonio foloseste mult expresia "pe mangleala" si cuvantul "gen".
* **Subtask 1 (30 puncte)**: <tex> 1 \leq N \leq 20 </tex>, <tex> M = 0 </tex>

* **Subtask 2 (20 puncte)**: <tex> 1 \leq N \cdot M \leq 4.000.000$ </tex>, <tex> 1 \leq M \leq 4.000 </tex> si nu vor exista $2$ angajati cu acelasi sef direct
* **Subtask 4 (50 puncte)**: <tex> 1 \leq N \leq 100.000 </tex>

* **Subtask 2 (20 puncte)**: <tex> 1 \leq N \cdot M \leq 4 000 000$ </tex>, <tex> 1 \leq M \leq 4 000 </tex> si nu vor exista $2$ angajati cu acelasi sef direct
* **Subtask 4 (50 puncte)**: <tex> 1 \leq N \leq 100 000 </tex>

h2. Exemplu