N,K=map(int,input().split())
A = [[int(x) for x in input()] for _ in range(N)]
res = []
for i in range(N):
    for j in [i,N-i-1]:
        if A[i][j]>=1:
            res.append((i,j))
print(len(res))
for i,j in res:
    print(i,j)