problem_C

int a[300000], n, k;

int main()
{
    ll ans, s = 0, f = 0;
    cin >> n >> k;
    for (int i = 0; i < n; i++)
        scanf("%d", &a[i]);
    sort(a, a + n);
    for (int i = 0; i < k; i++)
    {
        f += i * 1ll * a[i] - s;
        s += a[i];
    }
    ans = f;
    for (int i = k; i < n; i++)
    {
        s -= a[i - k];
        f -= -(k - 1) * 1ll * a[i - k] + s;
        f += (k - 1) * 1ll * a[i] - s;
        s += a[i];
        ans = min(ans, f);
    }
    cout << ans;
    return 0;
}