import sys
input = sys.stdin.readline
from collections import deque
def main() :
    H,W = map(int,input().split())
    A = [list(map(int,input().split())) for y in range(H)]
    ans = 0
    dxy = [(-1,0), (0,-1), (0,1), (1,0)]

    for i in range(H) :
        for j in range(W) :
            if A[i][j] != 1 :
                continue
            ans += 1
            A[i][j] = 0
            q = deque([(i, j)])
            while q :
                y, x = q.popleft()
                for dy,dx in dxy :
                    ny,nx = y+dy, x+dx
                    if ny<0 or ny>=H or nx<0 or nx>=W :
                        continue
                    if A[ny][nx] != 1 :
                        continue
                    q.append((ny, nx))
                    A[ny][nx] = 0
    print(ans)
main()