def solve(l, d):
    d = sorted([int(k) for k in d])
    if l % 2 == 0:
        minv = sum([abs(v - d[int(l/2)]) for v in d])
    else:
        minv = min(sum([abs(v - d[int(l/2)]) for v in d]),
                   sum([abs(v - d[int(l/2) + 1]) for v in d]))
    return minv

if __name__ == '__main__':
    l = int(input().split()[0])
    print(solve(l, input().split()))