from math import sqrt, log10

def isp(x):
  if x == 2:
    return True
  if x <= 1 or x & 1 == 0:
    return False
  for i in xrange(3, int(sqrt(x)) + 1, 2):
    if x % i == 0:
      return False
  return True


def test(x):
  sqr = int(sqrt((x - 1) / 2))
  for i in xrange(1, sqr + 1):
    tt = x - 2 * i * i
    if isp(tt):
      return True
  return False


n = 9
while 1:
  if not isp(n):
    if not test(n):
      print n
      break
  n += 2

#kkkk = input('end')