HPI4: Undamped Oscillations // Advanced

Bob the Knight is back, and he's stuck on the center of a one-dimensional plane. The plane can be modeled as a number line (with Bob initially at 0), and he sees an escape route located at coordinate M. Bob may either move to the left or right, but must move K steps on the K'th move. Please help bob determine the minimum number of steps required to reach M.

Input Format

Line 1: M, the coordinate location of the escape route

Sample Input

SAMPLE INPUT #1
20

SAMPLE INPUT #2
11

Output Format

Line 1: The minimum number of steps required to reach M, or "NONE" if this is not possible.

Sample Output

SAMPLE OUTPUT #1
7

SAMPLE OUTPUT #1
5