import heapq
import math
N,K = map(int,input().split())
M = max(-(-N//K),math.ceil(N))
HW = [['.']*M for _ in range(M)]

h = []
for i in range(M):
    h.append((0,i))
heapq.heapify(h)
cnt = 0

for i in range(M):
    cnt0 = 0
    while cnt0 != K:
        a,b = heapq.heappop(h)
        HW[i][b] = '#'
        heapq.heappush(h, (a+1,b))
        cnt0 += 1
        cnt += 1
        if cnt == N:
            break
    if cnt == N:
        break
print(M)
for i in range(M):
    print(*HW[i],sep='')