#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <iomanip>
#include <array>
#include <numeric>
#include <regex>
#include <bitset>
#include <deque>

using namespace std;
typedef long long ll;
typedef pair<int, int> p_ii;

const int INF = 1e9;
const double PI = acos(-1.0);
const ll MOD = 1e9 + 7;

int b, n;
int c[15];

ll f(ll x){
    ll t=0;
    for (int i = 0; i < n; i++) {
        t+=abs(c[i]-x);
    }
    return t;
}

int main() {
    ll total=0;
    cin>>b>>n;
    for (int i = 0; i < n; i++) {
        cin>>c[i];
        total+=c[i];
    }
    total+=b;

    ll left=0;
    ll right=total/n;
    while(right-left>0){
        ll d=(right-left)/3;
        ll l=f(left+d);
        ll r=f(right-d);
        if(d==0){
            if(l>r)left++;
            else right--;
        }else{
            if(l>r)left+=d;
            else right-=d;
        }
    }
    cout<<f(left)<<endl;

    return 0;
}