from collections import deque

h, w = map(int, input().split())
a = [list(map(int, input().split())) for _ in range(h)]

dx = [1, 0, -1, 0]
dy = [0, 1, 0, -1]

par = [[-1 for _ in range(w)] for _ in range(h)]
ans = 0
for x in range(h):
  for y in range(w):
    if a[x][y] == 0 or par[x][y] != -1:
      continue

    dq = deque()
    sx, sy = x, y
    dq.appendleft((sx, sy))
    par[sx][sy] = ans
    while len(dq) > 0:
      cx, cy = dq.pop()
      for i in range(4):
        nx = cx + dx[i]
        if nx < 0 or nx >= h:
          continue
        ny = cy + dy[i]
        if ny < 0 or ny >= w:
          continue
        if a[nx][ny] == 0 or par[nx][ny] != -1:
          continue

        par[nx][ny] = ans
        dq.appendleft((nx, ny))
    ans += 1

print(ans)