import numpy
N,K=map(int,input().split())
a=(N//(K*K))
b=0
if N<=K*K:
    a=0
    b=int(numpy.sqrt(N-1/2)+1)
elif not N%(K*K)==0:
    b=int(numpy.sqrt(N%(K*K)-1/2))+1
M=a*K+b
print(M)
for i in range(a):
    word='.'*(i*K)+'#'*K+'.'*(M-K*(i+1))
    for j in range(K):
        print(word)
last=N-K*K*a
for j in range(b):
    num=0
    if last>=b:
        last=last-b
        num=b
    elif last>0:
        num=last
        last=0
    word='.'*(a*K)+'#'*num+'.'*(M-a*K-num)
    print(word)