H,W=map(int,input().split())
A=[]
for i in range(H):
    A+=list(map(int,input().split()))

ANS=0
USE=[0]*(H*W)

for i in range(H):
    for j in range(W):
        if A[i*W+j]==1 and USE[i*W+j]==0:
            ANS+=1
            Q=[(i,j)]
            USE[i*W+j]=1
            while Q:
                x,y=Q.pop()
                for z,w in [(x+1,y),(x-1,y),(x,y+1),(x,y-1)]:
                    if 0<=z<H and 0<=w<W and A[z*W+w]==1 and USE[z*W+w]==0:
                        USE[z*W+w]=1
                        Q.append((z,w))

print(ANS)