N,K=map(int,input().split())


ANS=(N+(K-1))//K

while ANS*ANS<N:
    ANS+=1

print(ANS)
MAP=[["."]*ANS for i in range(ANS)]

now=N
for i in range(ANS):
    for j in range(min(K,ANS)):
        if now>0:
            MAP[i][(i+j)%ANS]="#"
            now-=1

for map in MAP:
    print("".join(map))