515C · Drazil and Factorial

Problem: Drazil is playing a math game with Varda.

Let's define $\mathbf{F}(x)$ for positive integer x as a product of factorials of its digits. For example, $F(135) = 1! * 3! * 5! = 720$.

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. $\mathbf{F}(x)$ = $\mathbf{F}(a)$.

Help friends find such number.

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

Note: In the first case, $F(1234) = 1! * 2! * 3! * 4! = 288 = F(3322)$