A decimal number $S$ of length $N$ consisting only of the characters $6$ and $7$ is given. You can delete at most $\lfloor \frac{N}{2} \rfloor$ characters from $S$. The relative order of the remaining characters does not change after deletion. By deleting characters appropriately, you want to make the remaining number a multiple of $6$ or a multiple of $7$. Print any one of the results that satisfy the condition.

The input is given in the following format.

$N$ $S$

Print the remaining number after deleting characters that satisfy the condition.

If there are multiple correct answers, you may print any of them. It is guaranteed that an answer always exists.

• $1 \le N \le 300\,000$.
• $S$ is a string of length $N$ consisting only of the characters $6$ and $7$.