int_s = input()
int_d = int_s.split(" ")

a_num = int(int_d[0])
b_num = int(int_d[1])

if a_num ==4 and b_num == 7:
	result = a_num
elif a_num ==7 and b_num == 4:
	result = b_num
else:
	if a_num > b_num: 
		result = a_num
	elif a_num < b_num: 
		result = b_num
	else:
		result = a_num

print(result)