n,k = map(int, input().split())
t = n//(k**2)
m = n - t*k*k
if not m:
    print(t*k)
    for i in range(t):
        v = '.'*i*k + '#'*k + '.'*(t-1-i)*k
        for j in range(k):
            print(v)
else:
    d = int((m-.5)**.5) + 1
    print(t*k+d)
    for i in range(t):
        v = '.'*i*k + '#'*k + '.'*((t-1-i)*k + d)
        for j in range(k):
            print(v)
    v = '.'*t*k + '#'*d
    for i in range(d):
        if m > d:
            print(v)
            m -= d
        else:
            print('.'*(t*k + d - m) + '#'*m)
            m -= m