N,K = map(int,input().split())
def func(n,k):#縦横マス数,一列の最大
    return (n//k)*k*k + (n%k)**2

for i in range(1,N+1):
    if N <= func(i, K):
        M = i
        break
HW = [['.']*M for _ in range(M)]
cnt= 0
for p in range(0,M,K):
    for l in range(p,min(p+K,M)):
        for m in range(p,min(p+K,M)):
            if cnt == N:
                break
            HW[l][m] = '#'
            cnt += 1
for l in range((M//K)*K,M):
    for m in range((M//K)*K,M):
        if cnt == N:
            break
        HW[l][m] = '#'
        cnt += 1
print(M)
for i in range(M):
    print(*HW[i],sep='')