#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = 1000000007;
const int INF = 1000000000;

#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)

int n;
int a[20];

ll func(int x){
    ll ret = 0;
    for (int i = 0; i < n; i++){
        ret += abs(a[i] - x);
    }
    return ret;
}

int main(){
    int b;
    cin >> b >> n;
    for (int i = 0; i < n; i++) cin >> a[i];

    int ng = -1;
    int ok = INF;
    while(abs(ok - ng) > 1){
        int mid = (ok + ng) / 2;
        if (func(mid) <= func(mid + 1)) ok = mid;
        else ng = mid;
    }

    cout << func(ok) << endl;

    return 0;
}