# -*- coding: utf-8 -*-
"""
No.609 Noelちゃんと星々
https://yukicoder.me/problems/no/609

"""
import sys
from sys import stdin
from statistics import median
input = stdin.readline


def solve(stars):
    stars.sort()
    m = median(stars)
    res = [abs(x - m) for x in stars]
    return sum(res)


def main(args):
    _ = input()
    stars = [int(x) for x in input().split()]
    ans = solve(stars)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])