Spadework 2020. 3. 15. 22:26

* Solved 기준 브론즈2 단순 풀이

r,c = map(int, input().split())
a,b = map(int, input().split())
for i in range(r):
	for _ in range(a):
		for j in range(c):
			print('.'*b if (i+j)%2 else 'X'*b, end='')
		print()