JOI’s Walk

JOI is taking a walk along a straight road. He alternates between the following two operations:

• Moving forward by 3 m
• Moving backward by 2 m

JOI starts at position 0. Given an integer X representing the number of operations performed, determine his final position.

The process can be formulated as follows:

$$\text{position} = 3 \times \lceil \frac{X}{2} \rceil - 2 \times \lfloor \frac{X}{2} \rfloor$$

Note that the 1^st, 3^rd, 5^th ... moves are forward moves and the 2^nd, 4^th, 6^th ... moves are backward moves.

inputFormat

The input consists of a single integer X (1 ≤ X ≤ 10⁹) representing the number of operations.

outputFormat

Output a single integer representing JOI's final position after X operations.

sample

1

3