Mock CCC '20 Contest 1 J5 - A Prime Problem

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Points: 12 (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

• commented on Feb. 29, 2020, 7:42 p.m. edit 3

Does N or D in the input have leading zeros?

I'm just wondering because I got WA on test case #642. It's probably because there is something else wrong with my program.

Edit: Fixed the error