Smooth numbers

Let's call positive integer smooth if each of its digits except the first and the last is less then the average of it's two neighbor digits. It means that if $x = a_n \cdot 10^n + a_{n-1} \cdot 10^{n-1} + ... + a_1 \cdot 10 + a_0$ then for each $i = 1 ... {n-1}$ the inequality $a_i < (a_{i - 1} + a_{i + 1}) / 2$ holds.

Vasya has been studying smooth numbers for a long time and he wants to know, if any smooth number of exactly $l$ digits exists, and if so, what is the greatest $l$-digit smooth number.

Vasya is asking you for help! Find the greatest $l$-digit smooth number.

Input file contains the only integer $l$ ($1 \le l \le 100$) --- number of digits in smooth number.

Output the greatest $l$-digit smooth number or $-1$ if it does not exist.