n = int(input())

a = []
for i in range(n):
    a.append(list(map(int, input())))

ans = []

for i in range(n):
    for j in range(n):

        if a[i][j] == 1:

            q = [[i, j]]
            a[i][j] = 0

            cnt = 1
            idx = 0

            while idx < len(q):

                x = q[idx][0]
                y = q[idx][1]
                idx += 1

                if x > 0 and a[x-1][y] == 1:
                    a[x-1][y] = 0
                    q.append([x-1, y])
                    cnt += 1

                if x < n-1 and a[x+1][y] == 1:
                    a[x+1][y] = 0
                    q.append([x+1, y])
                    cnt += 1

                if y > 0 and a[x][y-1] == 1:
                    a[x][y-1] = 0
                    q.append([x, y-1])
                    cnt += 1

                if y < n-1 and a[x][y+1] == 1:
                    a[x][y+1] = 0
                    q.append([x, y+1])
                    cnt += 1

            ans.append(cnt)

for i in range(len(ans)):
    for j in range(i + 1, len(ans)):
        if ans[i] > ans[j]:
            ans[i], ans[j] = ans[j], ans[i]

print(len(ans))

for x in ans:
    print(x)