#include <bits/stdc++.h>
using namespace std;

int main()
{
    
    int n, k;
    int avg_u = 0, avg_d = 0;
    cin >> n >> k;
    vector<int> v(n);
    for (auto &i : v)
        cin >> i;
    sort(v.rbegin(), v.rend());
    for (int i = 0; i < n - 1; i++)
    {
        avg_u += v[i];
        avg_d += *(v.end() - 1 - i);
    }
    cout << avg_u - avg_d;
    
    //system("pause");
}