import sys
import numpy as np
from scipy.sparse.csgraph import connected_components
from scipy.sparse import csr_matrix

input = sys.stdin.buffer.readline
H, W = map(int, input().split())
A = np.array([tuple(map(int, input().split())) for _ in range(H)], dtype=bool)
F = np.arange(H * W).reshape((H, W))

HC = A[1:] & A[:-1]
WC = A[:, 1:] & A[:, :-1]
frm = np.hstack((F[np.concatenate([np.zeros(W, dtype=bool).reshape(1, W), HC], 0)],
                 F[np.concatenate([np.zeros(H, dtype=bool).reshape(H, 1), WC], 1)]))
to = np.hstack((F[np.concatenate([HC, np.zeros(W, dtype=bool).reshape(1, W)], 0)],
                F[np.concatenate([WC, np.zeros(H, dtype=bool).reshape(H, 1)], 1)]))
L = len(frm)
matr = csr_matrix(([1] * L, (frm, to)), shape=(H * W, H * W))
p = connected_components(matr, return_labels=False)
ans = p - np.count_nonzero(~A)
print(ans)