Little C likes to collect treasure chests in a game called Abyss.

Little C is currently on a number line at the origin.

There are two treasure chests on this number line at coordinates $a$ and $b$, respectively.

As soon as Little C moves to the position of a treasure chest, he is considered to have collected it. Specifically, if Little C is at the position of a treasure chest initially, he collects it immediately; if both treasure chests are at the same position, he can collect both at the same time.

Little C can move one unit length in either the positive or negative direction along the number line in each step. Little C wants to know the minimum number of moves required to collect both treasure chests.

Input

Two integers $a$ and $b$.

Output

A single integer representing the minimum number of moves required for Little C to collect both treasure chests.

Examples

Input 1

1 -1

Output 1

3

Note 1

Little C can move in the negative direction $1$ time, then move in the positive direction $2$ times.

It can be proven that Little C needs at least $3$ moves.

Input 2

-5 0

Output 2

5

Note 2

Little C can move directly in the negative direction $5$ times.

It can be proven that Little C needs at least $5$ moves.

Input 3

51 -154

Output 3

256

Constraints

For $100\%$ of the data, $|a|, |b| \le 200$.