# encoding:utf-8
H ,W = map(int, input().split(' '))

str_line_1 = '#'
str_line_2 = '.'

# str_char = ['#','.']
def set_char(data):
    if data[len(data)-1] == '#':
        return '.'
    else: return '#'

for i in range(W - 1):
    str_line_1 += set_char(str_line_1)
    str_line_2 += set_char(str_line_2)

for i in range(H):
    if (i % 2) == 0:
        print(str_line_1)
    else:
        print(str_line_2)