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.
fact = [0 for x in range(10)]
fact[0] = int(1)
 

def backtrack(at, num, target):
    if num == 1:
        return target
    k = int(0);
    for i in range(at, 10):
        if num % fact[i] == 0:
            k = max(k, backtrack(at, num // fact[i], target * 10 + i))
    return k


def main():
    for i in range(1, 10):
        fact[i] =int(fact[i - 1] * i)
    n = int(input( ))
    k = int(input( ))
    n = 1;
    while k != 0:
        digit = int(k % 10)
        n = n * fact[digit]
        k = k // 10
    
    ans = backtrack(2, n, 0)
    print(ans)
            
if __name__ == "__main__":
    main( )