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.
def get_factorization(num):
    factorization = dict()
    divider = 2
    while num != 1:
        power = 0
        while num % divider == 0:
            num = num // divider
            power += 1
        factorization[divider] = power
        divider += 1
    return factorization


def get_factorization_factorial(num):
    factorization = dict()
    for index in range(2, num + 1):
        factorization_index = get_factorization(index)
        for prime, power in factorization_index.items():
            if prime in factorization:
                factorization[prime] += power
            else:
                factorization[prime] = power
    return factorization


def get_factorization_F(x):
    factorization = dict()
    digits = [int(digit) for digit in x if digit != '0' and digit != '1']
    for digit in digits:
        digit_factorization = get_factorization_factorial(digit)
        for prime, power in digit_factorization.items():
            if prime in factorization:
                factorization[prime] += power
            else:
                factorization[prime] = power
    return factorization


def get_largest_similar_num(x):
    x_factorization = get_factorization_F(x)
    primes = list(x_factorization.keys())
    primes.sort(reverse=True)
    result = []
    for prime in primes:
        power = x_factorization[prime]
        result += [prime] * power
        prime_factorial_factorization = get_factorization_factorial(prime)
        for second_prime, second_power in prime_factorial_factorization.items():
            x_factorization[second_prime] -= second_power * power
    return ''.join([str(digit) for digit in result])


def solve():
    input()
    x = input()
    result = get_largest_similar_num(x)
    print(result)


if __name__ == '__main__':
    solve()