x,y = map(int, input().split())

for l in range(x):
    for i in range(y):
        if l % 2 ==0:
            if i % 2 == 0:
                print ("#",end="")
            else:
                print (".",end="")
        else:
            if i % 2 == 0:
                print (".",end="")
            else:
                print ("#",end="")
    print ()

