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.
import sys
lines = sys.stdin.readlines()
N = int(lines[0].strip())
num = lines[1].strip()
factor = {2:{2:1}, 3: {3:1}, 4:{2:2}, 5:{5:1}, 6:{2:1, 3:1}, 7:{7:1}, 8:{2:3}, 9:{3:2}}

factorial = [{}, {}]

tmp = {}
for i in range(2, 10):
    for k in factor[i].keys():
        if k not in tmp: tmp[k] = 0
        tmp[k] += factor[i][k]
    factorial.append(tmp.copy())
target = {}
for l in num:
    for k in factorial[int(l)].keys():
        if k not in target: target[k] = 0
        target[k] += factorial[int(l)][k]
res = ""
if 7 in target:
    val = target[7]
    res += "7" * val
    for k in factorial[7].keys():
        target[k] -= factorial[7][k] * val

if 5 in target and target[5] > 0:
    val = target[5]
    res += "5" * val
    for k in factorial[5].keys():
        target[k] -= factorial[5][k] * val

if 3 in target and target[3] > 0:
    val = target[3]
    res += "3" * val
    for k in factorial[3].keys():
        target[k] -= factorial[3][k] * val
if 2 in target: res += "2" * target[2] 
print(res)