UNCA High School Programming Competition 2018

#### Start

2018-04-14 08:00 AKDT

## UNCA High School Programming Competition 2018

#### End

2018-04-14 12:00 AKDT
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# Problem FPersistent Numbers

The multiplicative persistence of a number is defined by Neil Sloane (Neil J.A. Sloane in The Persistence of a Number published in Journal of Recreational Mathematics 6, 1973, pp. 97-98., 1973) as the number of steps to reach a one-digit number when repeatedly multiplying the digits. For example:

$697 \rightarrow 378 \rightarrow 168 \rightarrow 48 \rightarrow 32 \rightarrow 6$

That is, the persistence of $697$ is $5$. The persistence of a single digit number is $0$. At the time of this writing it is known that there are numbers with the persistence of $11$. It is not known whether there are numbers with the persistence of $12$, but it is known that if they exist then the smallest of them would have more than $3000$ digits.

The problem that you are to solve here is: what is the smallest number such that the first step of computing its persistence results in the given number?

## Input

The input consists of multiple test cases. Each line contains a test case, which consists of a decimal number with up to $1\, 000$ digits. The input ends with a line containing -1.

There will be at most $50$ test cases in a single input file.

## Output

For each testcase, output a single line containing one integer number satisfying the condition stated above. If no such number exists, output “There is no such number”.

Sample Input 1 Sample Output 1
0
1
4
7
18
49
51
768
-1

10
11
14
17
29
77
There is no such number.
2688