package main
import (
    "fmt"
    "sort"
)

const N int = 100000
var s [N]int

func main() {
    var n int
    fmt.Scanf("%d", &n)

    for i := 0; i < n; i++ {
        fmt.Scanf("%d", &s[i])
    }

    sort.Ints(s[0:n])
    res := 0
    for i := 0; i < n; i++ {
        num := (s[i] - s[n/2])
        if num < 0 {
            num = -1 * num
        }
        res += num
    }

    fmt.Printf("%d\n", res)
}