positions = (2,4,6,8,10,12,14)
result = "1_2_3_4_5_6_7_8_9_0"

number = 1000000030
state = True

while number <= 3162277630:
	number += 40 if state else 60
	state = not state

	found = True

	square = str(number**2)
	for i in positions:
		if square[i] != result[i]:
			found = False
			break

	if found:
		break

print number