# Simple numbers

A number is termed "simple" if it can be divided into two segments, each containing at least d digits (with neither segment beginning with 0), such that both segments are prime numbers. Recall that prime numbers are natural numbers with exactly two distinct divisors. You are provided with a pair of numbers d and n. Your task is to find and output the smallest simple number that is not less than n.

## Input

The input consists of one or more sets of data. Each set is presented on a separate line and contains a pair of natural numbers d and n, separated by a space (1 ≤ d ≤ 5; 1 ≤ n ≤ 2·10^9). There will be no more than 5 sets of input data in the test.

## Output

For each set, output the required number on a separate line. It is guaranteed that the solution for any set will not exceed 2·10^9.