#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import array
import statistics


def solve(candies):
    median = statistics.median_low(candies)
    return sum(map(lambda c: abs(c - median), candies))


def main():
    b = int(input())
    n = int(input())
    candies = array.array("L", (int(input()) for _ in range(n)))
    print(solve(candies))


if __name__ == '__main__':
    main()