You have a counter that initially shows the number $0$. In one move you can either increase the counter by $11$ or decrease it by $2$, but the counter can never be less than $0$ or more than $x$. Find the minimum amount of moves you need in order to make the counter show $x$ or report that the task is impossible.

Input

The first line contains the integer $x$.

Output

Print the minimum number of moves required to make the counter show $x$ or $-1$ if the task is impossible.

Constraints

• $0 \leq x \leq 10^6$

Example 1

Input:

62

Output:

8

Example 2

Input:

1

Output:

-1

Example 3

Input:

0

Output:

0