while True:
    h,w = map(int,input().split())
    def bw(x):
        if x % 2 == 0:
            print((x//2)*('#.'))
        elif x % 2 == 1:
            print((x//2)*('#.')+'#')
    def wb(x):
        if x % 2 == 0:
            print((x//2)*('.#'))
        elif x % 2 == 0:
            print((x//2)*('.#')+'.')
    for i in range(h+1):
        if i % 2 == 0:
            bw(w)
        else:
            wb(w)
    print(i)
            