// https://yukicoder.me/problems/no/609

package main

import (
	"fmt"
	"sort"
)

func diff(a, b int) int {
	if a > b {
		return a - b
	}
	return b - a
}

func main() {
	var n int
	fmt.Scan(&n)
	ys := make([]int, n)
	for i := 0; i < n; i++ {
		fmt.Scan(&ys[i])
	}

	sort.Ints(ys)
	med := ys[n/2]

	sum := 0
	for _, y := range ys {
		sum += diff(med, y)
	}
	fmt.Println(sum)
}