import sys
from collections import deque

input = sys.stdin.readline

def BFS(filedMap, visited, x, y, N):
    queue = deque([(x,y)])
    visited[y][x] = True
    cnt = 1
    
    dx = [1,-1,0,0]
    dy = [0,0,1,-1]
    
    while len(queue):
        cx, cy = queue.popleft()
        for i in range(4):
            nx, ny = cx + dx[i], cy + dy[i]
            if 0<=nx<N and 0<=ny<N and not visited[ny][nx] and filedMap[ny][nx]==1:
                queue.append((nx,ny))
                visited[ny][nx] = True
                cnt += 1
    return cnt

N = int(input())
filedMap = []
visited = [[False]*N for _ in range(N)]
for _ in range(N):
    filedMap.append(list(map(int,[s for s in input().rstrip()])))

cntEstate = []
for i in range(N):
    for j in range(N):
        if not visited[i][j] and filedMap[i][j] > 0 :
            cntEstate.append(BFS(filedMap, visited, j, i, N))

result = str(len(cntEstate)) + '\n' + '\n'.join(map(str, sorted(cntEstate)))
print(result)