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.
n = int(input())
a = [int(i) for i in input()]

digit = [0 for i in range(10)]

for i in range(n):
	if a[i] > 1:
		if a[i] == 4:
			digit[3] += 1
			digit[2] += 2
		elif a[i] == 6:
			digit[5] += 1
			digit[3] += 1
		elif a[i] == 8:
			digit[7] += 1
			digit[2] += 3
		elif a[i] == 9:
			digit[7] += 1
			digit[3] += 2
			digit[2] += 1

		else:
			digit[a[i]] += 1
# print(digit)
num = ''
i = 9
while i > 1:
	while i > 1 and digit[i] < 1:
		i -= 1
	if i > 1:
		num += str(i)
		digit[i] -= 1

print(num) 