import java.util.ArrayList;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        new Main().run();
    }

    void run() {
        try (final Scanner in = new Scanner(System.in)) {
            int n = in.nextInt();
            int k = in.nextInt();
            int[][] d = new int[n][n];
            for (int r = 0; r < n; r++) {
                String line = in.next();
                for (int c = 0; c < n; c++) {
                    d[r][c] = line.charAt(c) - '0';
                }
            }

            ArrayList<Point> points = new ArrayList<>();
            for (int i = 0; i < n; i++) {
                if (d[i][i] != 0) {
                    points.add(new Point(i, i));
                }
                if (d[i][n - 1 - i] != 0) {
                    points.add(new Point(i, n - 1 - i));
                }
            }

            System.out.println(points.size());
            for (Point p : points) {
                System.out.println(p.r + " " + p.c);
            }
            System.out.flush();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class Point {
    int r;
    int c;

    public Point(int r, int c) {
        this.r = r;
        this.c = c;
    }

}