# 固定出力でいけるやんwと慢心しWA :(
N, K = map(int, input().split())
D = []
for i in range(N):
    S = input()
    L = []
    for j in range(N):
        L.append(int(S[j]))
    D.append(L)

Ans = []
for i in range(N):
    if(D[i][25] != 0):
        Ans.append((i, 25))
for i in range(N):
    if(i == 25):
        continue
    if(D[25][i] != 0):
        Ans.append((25, i))
print(len(Ans))
for (i, j) in Ans:
    print(i, j)