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.

import sys, math
from collections import Counter, deque
from itertools import permutations

#########################
# Delete when submit
# sys.stdin = open("input.txt", "r")
# sys.stdout = open("output.txt", "w")
#########################


n = int(input())
s = str(input())

d = {         
        0: [], 
        1: [], 
        2: [2], 
        3: [3],
        4: [2, 2, 3],
        5: [5],
        6: [5, 3],
        7: [7],
        8: [2, 2, 2, 7],
        9: [3, 3, 2, 7]
    }

digits = []

for x in s:
    for i in d[int(x)]:
        digits.append(i)

digits.sort(reverse=True)

for _ in digits:
    print(_, end='')