import sys
sys.setrecursionlimit(1000000000)

#
# Solution Template for Yet Another Lights Problem
# 
# Australian Informatics Olympiad 2023
# 
# This file is provided to assist with reading of input and writing of output 
# for the problem. You may modify this file however you wish, or
# you may choose not to use this file at all.
#

# R is the number of rows.
R = 0

# C is the number of columns.
C = 0

# grid contains the initial state of each light.
grid = []

# Read the values of R, C and the initial state of each light.
R, C = map(int, input().strip().split())
grid = [ input().strip() for i in range(R) ]

# TODO: This is where you should compute your solution.

# You should append your cross-flips as tuples into the list cross_flips. For
# example, to include a cross-flip at position (2, 3), you should do
# cross_flips.append((2, 3)).
cross_flips = []

# If it is impossible to turn all the lights on, you should set is_impossible
# to True.
is_impossible = False

# Write the answers.
if is_impossible:
    print("-1")
else:
    print(len(cross_flips))
    for flip in cross_flips:
        print(flip[0], flip[1])