from collections import deque
import sys
input = sys.stdin.readline

def readlines(n):
	for h in range(n):
		for w, bit in enumerate(input().split()):
			if bit == "1":
				yield h,w
	
def main():
    H, W = map(int, input().split())
    A = set(readlines(H))
    dire = [(-1,0),(0,1),(1,0),(0,-1)]
    size = len(A)
    ans = 0
    for h,w in A.copy():
        if size < 0:
            break
        if (h,w) not in A:
            continue
        ans += 1
        frontier = deque()
        frontier.append((h, w))
        while frontier:
            y, x = frontier.popleft()
            for d, r in dire:
                suc_y = y+d
                suc_x = x+r
                if (suc_y, suc_x) not in A:
                    continue
                frontier.append((suc_y, suc_x))
                A.remove((suc_y,suc_x))
                size -= 1

    print(ans)

main()