#!/usr/bin/env python3


import itertools


def div_ceil(a, b):
    return (a + b - 1) // b


def construct(n, k):
    rest = n
    m = div_ceil(n, k)
    board = [["." for _ in range(m)] for _ in range(m)]
    for i in range(0, m, k):
        for dr, dc in itertools.product(range(k), repeat=2):
            r, c = i + dr, i + dc
            if 0 <= r < m and 0 <= c < m and rest > 0:
                board[r][c] = "#"
                rest -= 1
    return m, board


def main():
    n, k = (int(z) for z in input().split())
    m, board = construct(n, k)
    print(m)
    print(*("".join(line) for line in board), sep="\n")


if __name__ == "__main__":
    main()