## Mock CCC '20 Contest 1 J5 - A Prime Problem

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Points: 7 (partial)
Time limit: 0.5s
Memory limit: 1G

Problem type

koosaga likes numbers which are constructed by concatenating two prime numbers together. A number which can be formed by concatenating two primes that both have at least digits is a -level prime pair certificate. Leading zeroes are not permitted.

Given two integers and , compute the smallest -level prime pair certificate greater than or equal to .

#### Constraints

The output will never exceed .

There are no subtasks for this problem.

#### Input Specification

The input will consist of two positive space separated integers, and .

#### Output Specification

Output the smallest -level prime pair certificate greater than or equal to .

#### Sample Input

2 11328

#### Sample Output

11329