n,k = map(int,input().split())
cdd = (n+(k-1))//k
f = False
if cdd < k:
    tmp = cdd
    while tmp**2 < n:
        tmp += 1
    m = tmp
    f = True
else:
    m = cdd
print(m)

ans = [[""]*m for i in range(m)]
if f == True:
    cnt = n
    for i in range(m):
        for j in range(m):
            if cnt > 0:
                cnt -= 1
                ans[i][j] = "#"
            else:
                ans[i][j] = "."
else:
    cnt = n
    for i in range(m):
        lm = k
        for j in range(m):
            if cnt > 0 and lm > 0:
                cnt -= 1
                lm -= 1
                ans[i][(j+i)%m] = "#"
            else:
                ans[i][(j+i)%m] = "."


for i in range(m):
    print(*ans[i],sep="")