from math import ceil
N,K = map(int,input().split())
cnt = 0
M = max(-(-N//K),ceil(N**0.5))
A = [["."] * M for _ in range(M)]
for i in range(M):
    for j in range(i,i+min(K,M)):
        if cnt < N:
            A[i][j % M] = "#"
            cnt += 1
print(len(A))
for a in A:
    print("".join(a))