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.
input()
d ={}
a = input()
for i in a:
	if i=="1" or i=="0":pass
	else:
		if int(i)%2!=0 or i == "2":
			if i=="9":
				if 2 in d:d[2]+=1
				else:d[2]=1
				if 3 in d:d[3]+=2
				else:d[3]=2
				if 7 in d:d[7]+=1
				else:d[7]=1
			else:
				if int(i) in d:d[int(i)]+=1
				else:d[int(i)]=1
		else:
			if i=="4":
				if 2 in d:d[2]+=2
				else:d[2]=2
				if 3 in d:d[3]+=1
				else:d[3]=1
			elif i=="6":
				if 3 in d:d[3]+=1
				else:d[3]=1
				if 5 in d:d[5]+=1
				else:d[5]=1
			elif i=="8":
				if 2 in d:d[2]+=3
				else:d[2]=3
				if 7 in d:d[7]+=1
				else:d[7]=1
ans =""
for i in range(9,1,-1):
	if i in d:
		ans+=str(i)*d[i]
print(ans)