import sys
readline=sys.stdin.readline

N,K=map(int,readline().split())
H=max((N+K-1)//K,int((N-1)**.5)+1)
K=min(K,H)
ans_lst=[["."]*H for h in range(H)]
for i in range(H):
    for j in range(i,i+K):
        if N:
            ans_lst[i][j%H]="#"
            N-=1
print(H)
for ans in ans_lst:
    print(*ans,sep="")