def Ceil_Root(a,k):
    """ceil(a^(1/k)) を求める.

    a:非負整数
    k:正の整数
    """
    assert 0<=a and 0<k
    if a==0:
        return 0
    if k==1:
        return a

    #大体の値を求める.
    x=int(pow(a,1/k))+1

    #増やす
    while pow(x,k)<a:
        x+=1

    #減らす
    while a<=pow(x-1,k):
        x-=1
    return x
#==================================================
N,K=map(int,input().split())

L=float("inf")
for m in range(1,K+1):
    q,r=divmod(N,m*m)
    s=Ceil_Root(r,2)

    if q*m+s<L:
        L=q*m+s
        M=m
        Q=q
        S=s

print(L)
X=[["."]*L for _ in range(L)]
for k in range(Q):
    for i in range(k*M, (k+1)*M):
        for j in range(k*M, (k+1)*M):
            X[i][j]="#"

R=N-Q*M*M
for i in range(Q*M,L):
    for j in range(Q*M,L):
        if R>0:
            R-=1
            X[i][j]="#"

for x in X:
    print(*x,sep="")