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

def main():
    H, W = map(int, input().split())
    A = [list(map(int, input().split())) for _ in range(H)]
    dire = [(-1,0),(0,1),(1,0),(0,-1)]
    explored = set()
    ans = 0
    for h in range(H):
        for w in range(W):
            if A[h][w] == 0 or (h, w) in explored:
                continue
            ans += 1
            frontier = deque()
            frontier.append((h, w))
            explored.add((h, w))
            while frontier:
                y, x = frontier.popleft()
                for d, r in dire:
                    suc_y = y+d
                    suc_x = x+r
                    if suc_y >= H or suc_x >= W or \
                        suc_y < 0 or suc_x < 0 or \
                        (suc_y, suc_x) in explored or \
                        A[suc_y][suc_x] == 0:
                        continue

                    frontier.append((suc_y, suc_x))
                    explored.add((suc_y, suc_x))

    print(ans)

main()