<?php

/**
 * @see https://yukicoder.me/problems/75
 */


// main
$X = trim(fgets(STDIN));
$Y = trim(fgets(STDIN));
$L = trim(fgets(STDIN));

$robot = new Robot($L);
$ret = $robot->move($X, $Y);
echo $ret . "\n";

class Robot
{
    /** @var array 現在いる座標*/
    private $position;
    /** @var string 現在向いている方向*/
    private $orientation;
    /** @var integer 一回の前進で移動できる最大値 */
    private $maxMigrationLength;
    /** @var RegisterExecHistoryCommand */
    private $RegisterExecHistoryCommand;

    public function __construct(int $maxMigrationLength)
    {
        $this->position = [0, 0];
        $this->orientation = Direction::NORTH;
        $this->maxMigrationLength = $maxMigrationLength;
    }

    /**
     * 指定された座標に移動する
     *
     * @param integer $x
     * @param integer $y
     * @return void 
     */
    public function move(int $x, int $y): int
    {
        $positionType = $this->getPositionType($x, $y);
        switch ($positionType) {
            case PositonType::ZERO:
                return 0;
            case PositonType::ON_X:
                return $this->calcCntExceed($x) + 1;
            case PositonType::ON_Y:
                return $this->calcCntExceed($y) + (($y > 0) ? 0 : 1);
            case PositonType::FIRST_QUADRANT:
            case PositonType::SECOND_QUADRANT:
                return $this->calcCntExceed($x) + $this->calcCntExceed($y) + 1;
            case PositonType::THIRD_QUADRANT:
            case PositonType::FOURTH_QUADRANT:
                return $this->calcCntExceed($x) + $this->calcCntExceed($y) + 2;
        }
    }

    private function calcCntExceed($num)
    {
        return ceil(abs($num) / $this->maxMigrationLength);
    }

    private function getPositionType(int $x, int $y): int
    {
        if ($x == 0 && $y == 0) {
            return PositonType::ZERO;
        } elseif ($x != 0 && $y == 0) {
            return PositonType::ON_X;
        } elseif ($x == 0 && $y != 0) {
            return PositonType::ON_Y;
        } elseif ($x > 0 && $y > 0) {
            return PositonType::FIRST_QUADRANT;
        } elseif ($x < 0 && $y > 0) {
            return PositonType::SECOND_QUADRANT;
        } elseif ($x < 0 && $y < 0) {
            return PositonType::THIRD_QUADRANT;
        } elseif ($x > 0 && $y < 0) {
            return PositonType::FOURTH_QUADRANT;
        }
    }
}

class PositonType
{
    public const FIRST_QUADRANT = 1;
    public const SECOND_QUADRANT = 2;
    public const THIRD_QUADRANT = 3;
    public const FOURTH_QUADRANT = 4;
    public const ON_X = 5;
    public const ON_Y = 6;
    public const ZERO = 7;
}

class Direction
{
    public const NORTH = 0;
    public const SOUTH = 1;
    public const EAST = 2;
    public const WEST = 3;
}