Wonderprime Brands

The cows are forever competing to see who has the best brand, and the latest craze is a brand that is a "wonderprime". A brand is a sequence of digits that does not begin with $0$, so it looks just like a positive integer.

A wonderprime is a positive integer whose digit string can be split into two consecutive parts — a left part and a right part, whose concatenation is the original number — such that both parts are prime, each part has at least $D$ digits, and neither part begins with $0$.

For example, when $D=2$, the number $11329$ is a wonderprime, because it splits into $113$ and $29$, both of which are prime.

Given an integer $N$, find the smallest wonderprime that is greater than or equal to $N$. It is guaranteed that $1 \le N \le 2{,}000{,}000{,}000$ and that the answer never exceeds $2{,}000{,}000{,}000$.

The first line contains two space-separated integers $D$ and $N$.

Print the smallest wonderprime that is no smaller than $N$.