import java.util.Scanner
import kotlin.math.abs

val scanner = Scanner(System.`in`)

val listLeft = ArrayList<Int>()
val listRight = ArrayList<Int>()

while (scanner.hasNextInt()) {
    val num1 = scanner.nextInt()
    listLeft.add(num1)

    val num2 = scanner.nextInt()
    listRight.add(num2)
}

val pairs = listLeft.sorted() zip listRight.sorted()

val result = pairs.fold(0) { acc, (l, r) -> acc + abs(l - r) }

println(result)