N, K = map(int, input().split())
d, r = divmod(N, K**2)
k = 0
while k**2 < r:
    k += 1
A = d*K + k
print(A)
R = [['.']*A for i in range(A)]
for i in range(d):
    e = K*i
    for i in range(K):
        for j in range(K):
            if N > 0:
                R[e+i][e+j] = '#'
                N -= 1
e = K*d
for i in range(k):
    for j in range(k):
        if N > 0:
            R[e+i][e+j] = '#'
            N -= 1
for line in R:
    print(*line, sep='')