def pick(x, lis, out, a = 0):
  if x == 0:
    out.append(a)
    return
  a *= 10
  for i in xrange(len(lis)):
    tmp = lis[:]
    tmpa = a + lis[i]
    tmp.pop(i)
    pick(x - 1, tmp, out, tmpa)


def isprime(x):
  if x == 2:
    return True
  if x % 2 == 0:
    return False
  temp = 3
  while temp <= int(x ** 0.5) + 1:
    if x % temp == 0: return False
    else: temp += 2
  return True


a = [1,2,3,4,5,6,7]
tt = []
pick(len(a), a, tt)
tt.reverse()
for i in tt:
  if isprime(i):
    print i
    break