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.
from bisect import bisect
from itertools import accumulate
def get(f): return f(input().strip())
def gets(f): return [*map(f, input().split())]


a = [0, 0, 0, 0]
#     0  1  2  3  4  5  6  7  8  9
a2 = [0, 0, 1, 1, 3, 3, 4, 4, 7, 7]
a3 = [0, 0, 0, 1, 1, 1, 2, 2, 2, 5]
a5 = [0, 0, 0, 0, 0, 1, 1, 1, 1, 1]
a7 = [0, 0, 0, 0, 0, 0, 0, 1, 1, 1]
get(int)
for i in map(int, get(str)):
    a[0] += a2[i]
    a[1] += a3[i]
    a[2] += a5[i]
    a[3] += a7[i]
s = ''
while a[3]:
    s += '7'
    a[0] -= a2[7]
    a[1] -= a3[7]
    a[2] -= a5[7]
    a[3] -= a7[7]
while a[2]:
    s += '5'
    a[0] -= a2[5]
    a[1] -= a3[5]
    a[2] -= a5[5]
while a[1]:
    s += '3'
    a[0] -= a2[3]
    a[1] -= a3[3]
while a[0]:
    s += '2'
    a[0] -= a2[2]
print(s)
