h,w = map(int,input().split())
a = [list(map(int,input().split())) for _ in range(h)]

def dfs(i,j):
    a[i][j] = 0
    q = [(i,j)]
    while q:
        i,j = q.pop()
        for ni,nj in [(i+1,j),(i-1,j),(i,j+1),(i,j-1)]:
            if 0 <= ni < h and 0 <= nj < w and a[ni][nj] == 1:
                a[ni][nj] = 0
                q.append((ni,nj))

ans = 0
for i in range(h):
    for j in range(w):
        if a[i][j] == 1:
            ans += 1
            dfs(i,j)
print(ans)