Paras is participating in UCS organised by ACM-CSS. In that contest he comes across a problem which he is finding difficult to solve. So, he requests you to help him solve this problem.
Let's define F(x) for positive integer x as a product of factorials of its digits.
For example, 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. F(x)=F(a)

Help Paras to find such number.

Input:
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.

Output:
Output a maximum possible integer satisfying the conditions above. There should be no zeroes and ones in this number decimal representation.