import kotlin.math.abs

fun main() {
    val builder = StringBuilder()

    val x = readInputLine().toInt()
    val y = readInputLine().toInt()
    val l = readInputLine().toInt()

    if (x == 0 && y == 0) {
        builder.appendln(0)
    } else if (x == 0) {
        builder.appendln((abs(y) + l - 1) / l + if (y < 0) 2 else 0)
    } else if (y == 0) {
        builder.appendln((abs(x) + l - 1) / l + 1)
    } else {
        builder.appendln((abs(y) + l - 1) / l + (abs(x) + l - 1) / l + 1 + if (y < 0) 1 else 0)
    }

    print(builder.toString())
}

fun readInputLine(): String {
    return readLine()!!
}