Output Format

This problem uses Special Judge.

First output a single integer $k$, the maximum number of guards that can be placed.

Then output $k$ lines. Each line contains two integers $x, y$, indicating that a guard is placed at row $x$ and column $y$.

3 4
2 0 0 0
2 2 2 1
0 1 0 2

2
1 2
3 3

Hint

Explanation for sample input and output 1:

As shown in the figure (black cells are walls, white cells are empty, circles are traps, and G denotes a guard).

Constraints:

For all testdata, it is guaranteed that $1 \leq m, n \leq 200$ and $0 \leq a_{i, j} \leq 2$.

Translated by ChatGPT 5