4 5
1 1 0 0 0
1 1 0 0 0
0 0 1 0 0
0 0 0 1 1

3

from collections import deque
n, m = map(int, input().split())
grid = [list(map(int, input().split())) for _ in range(n)]
visited = [[False]*m for _ in range(n)]
count = 0
for r in range(n):
    for c in range(m):
        if grid[r][c] == 1 and not visited[r][c]:
            count += 1
            q = deque([(r, c)])
            visited[r][c] = True
            while q:
                cr, cc = q.popleft()
                for dr, dc in [(-1,0),(1,0),(0,-1),(0,1)]:
                    nr, nc = cr+dr, cc+dc
                    if 0<=nr<n and 0<=nc<m and not visited[nr][nc] and grid[nr][nc]==1:
                        visited[nr][nc] = True
                        q.append((nr, nc))
print(count)