n,k = map(int,input().split())
m = (n+k-1)//k
while m*m < n:
    m += 1
r = [[0]*m for _ in range(m)]
cnt = 0
print(m)
def f(x): return ".#"[x]
for i in range(m):
    for j in range(min(m,k)):
        r[i][(i+j)%m] = 1
        cnt += 1
        if cnt == n:
            for ri in r:
                print("".join(map(f,ri)))
            exit()