from collections import deque

h,w=map(int,input().split())
grid=[list(map(int,input().split())) for i in range(h)]
f=[[0]*w for i in range(h)]
cnt = 1
l=[1,0,-1,0]
r=[0,1,0,-1]


for i in range(h):
    for j in range(w):
        if grid[i][j] == 1 and f[i][j] ==0:
            d=deque()
            d.append((i,j))
            while d:
                x,y=d.popleft()
                f[x][y] = cnt
                for k in range(4):
                    if 0 <= x + l[k] < h and 0 <= y + r[k] < w:
                        if grid[x+l[k]][y+r[k]] == 1 and f[x+l[k]][y+r[k]] == 0:
                            d.append((x+l[k],y+r[k]))
            cnt+=1
print(cnt-1)