#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)


def main():
    N = int(input())
    Y = sorted(list(map(int, input().split())))

    n = N // 2
    d = sum(abs(y - Y[n]) for y in Y)
    print(d)

if __name__ == '__main__':
    main()