Description

In the residential area on Planet X, all buildings are identical and are arranged in a grid. The buildings are numbered $1, 2, 3, \cdots$.

When one row is filled, the numbering in the next row continues from the adjacent building but in the opposite direction.

For example, when the row width is $6$, the numbering starts like this:

1  2  3  4  5  6
12 11 10 9  8  7
13 14 15 .....

The task is: given two building numbers $m$ and $n$, find the shortest moving distance between them. (Diagonal movement is not allowed.)

Input Format

The input contains $3$ integers $w, m, n$ separated by spaces, all in the range from $1$ to $10000$.

Here, $w$ is the row width, and $m, n$ are the building numbers to compute.

Output Format

Output one integer, representing the shortest moving distance between buildings $m$ and $n$.

6 8 2

4

4 7 20

5

Hint

Time limit: 1 second, 256M.

Lanqiao Cup 2015 Provincial Contest Group B, Problem H.

Translated by ChatGPT 5