Drazil is playing a math game with Varda.

Let's define <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/7020b94c48be2ee5b8eeca05f379c8911bb0e7c4.png" style="max-width: 100.0%;max-height: 100.0%;"/> for positive integer *x* as a product of factorials of its digits. For example, <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/6784d861d9a724d0aeddefcb00b7d0c3442ae586.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

First, they choose a decimal number *a* consisting of *n* digits that contains at least one digit larger than 1. This number may possibly start with leading zeroes. Then they should find maximum positive number *x* satisfying following two conditions:

1. *x* doesn't contain neither digit 0 nor digit 1.

2. <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/7020b94c48be2ee5b8eeca05f379c8911bb0e7c4.png" style="max-width: 100.0%;max-height: 100.0%;"/> = <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/aa57e017a6c74d06b0a54bc47e3f6990e5af38c1.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

Help friends find such number.
The first line contains an integer *n* (1 ≤ *n* ≤ 15) — the number of digits in *a*.

The second line contains *n* digits of *a*. There is at least one digit in *a* that is larger than 1. Number *a* may possibly contain leading zeroes.

n = int(input())
num = input()

record = dict()
record[2] = 0
record[3] = 0
record[5] = 0
record[7] = 0

use = [ 2, 3, 5, 7]

for i in range(0,n):
  t = int( num[i] )

  while t > 1:
    dummy = t
    
    for j in use:
      while dummy%j == 0:
        dummy /= j
        record[j] += 1

    t -= 1

while record[7] > 0:
  print( 7, end = '')
  record[7] -= 1
  record[5] -= 1
  record[3] -= 2
  record[2] -= 4

while record[5] > 0:
  print( 5, end = '')
  record[5] -= 1
  record[3] -= 1
  record[2] -= 3

while record[3] > 0:
  print(3, end = '')
  record[3] -= 1
  record[2] -= 1

while record[2] > 0:
  print(2, end = '')
  record[2] -= 1

