from math import sqrt

n = 37
p = 2
q = int(sqrt(n)) + 1
czynnik_max = p
k = 1
d = -1

while p <= q:
	while n % p == 0:
		n /= p
		czynnik_max = p
	if n == 1:
		break
	if p < 3:
		p += 1
	else:
		p = 6*k + d
		if d == 1:
			d = -1
			k += 1
		else:
			d = 1
if n > 1:
	czynnik_max = n
print(int(czynnik_max))