N, K = map(int, input().split())
shou, amari = divmod(N, K**2)

for i in range(1000):
    if i ** 2 >= amari:
        M = shou*K + i
        break

ans = [['.'] * M for _ in range(M)]

for i in range(shou):
    for j in range(i*K, i*K+K):
        for k in range(i*K, i*K+K):
            ans[j][k] = '#'

for i in range(shou*K, M):
    for j in range(shou*K, M):
        ans[i][j] = '#'
        amari -= 1
        
        if amari == 0:
            break
    else:
        continue
    break

print(M)

for ans_i in ans:
    print(''.join(ans_i))