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


H,W=map(int,readline().split())
A=[list(map(int,readline().split())) for h in range(H)]
ans=0
seen=[[False]*W for h in range(H)]
for h in range(H):
    for w in range(W):
        if not seen[h][w] and A[h][w]:
            queue=[(h,w)]
            seen[h][w]=True
            ans+=1
            while queue:
                hh,ww=queue.pop()
                for dh,dw in ((0,1),(1,0),(0,-1),(-1,0)):
                    if 0<=hh+dh<H and 0<=ww+dw<W and A[hh+dh][ww+dw] and not seen[hh+dh][ww+dw]:
                        queue.append((hh+dh,ww+dw))
                        seen[hh+dh][ww+dw]=True
print(ans)