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.
'''
# Submitted By M7moud Ala3rj
Don't Copy This Code, CopyRight . [email protected] © 2022-2023 :)
'''
# Problem Name = "Drazil and Factorial"
# Class: C

import sys

#sys.setrecursionlimit(2147483647)
input = sys.stdin.readline
def print(*args, end='\n', sep=' ') -> None:
    sys.stdout.write(sep.join(map(str, args)) + end)

def Solve():
    n = int(input())
    d = {"4": "322", "6":"53", "8":"7222"}
    x = input().strip()
    x = x.replace("4", d["4"]).replace("6", d["6"]).replace("8", d["8"]).replace("1", "").replace("0", "")
    print("".join(sorted(x, reverse=True)))


if __name__ == "__main__":
    # for t in range(int(input())):
        Solve()