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

def main():
    H, W = map(int, input().split())
    A = [[[(False if c == "0" else True), False] for c in input().split()] for _ in range(H)]
    dire = [(-1,0),(0,1),(1,0),(0,-1)]
    ans = 0
    for h in range(H):
        for w in range(W):
            if not A[h][w][0] or A[h][w][1]:
                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 >= H or suc_x >= W or \
                        suc_y < 0 or suc_x < 0 or \
                        A[suc_y][suc_x][1] or \
                        not A[suc_y][suc_x][0]:
                        continue

                    frontier.append((suc_y, suc_x))
                    A[suc_y][suc_x][1] = True

    print(ans)

main()