#!/usr/bin/python2
# -*- coding: utf-8 -*-
# †
n = int(raw_input())
y = map(float, raw_input().split())

# 高さを決めたときの、距離の総和を求める
def calc(height):
    res = 0
    for i in xrange(n):
        res += abs(height - y[i])
    return res

lo, hi = 0, 10**20

for _ in xrange(200):
    m1 = (lo + lo + hi) / 3.
    m2 = (lo + hi + hi) / 3.
    if calc(m1) < calc(m2):
        hi = m2
    else:
        lo = m1
res = calc(lo)
ires = int(res)
assert abs(res - ires) < 1e-9
print ires