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.
if __name__ == "__main__":
    num = int(input())
    digits = input()
    temp = ""
    result = ""
    for i in range(0, num):
        # 0 or 1
        if (digits[i] == "0" or digits[i] == "1"):
            temp += ""
        # prime numbers
        elif (digits[i] == "2" or digits[i] == "3" or digits[i] == "5" or digits[i] == "7"):
            temp += digits[i]
        # composit numbers
        else:
            if (digits[i] == "4"):
                temp += "322"
            elif (digits[i] == "6"):
                temp += "53"
            elif (digits[i] == "8"):
                temp += "7222"
            elif (digits[i] == "9"):
                temp += "7332"
    tempStr = str(temp)
    result = ''.join(sorted(tempStr, reverse = True)) 
    print(result)