#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

template <typename T> class segTree
{
private:
  const T e;
  int num;
  std::vector<T> dat;
  T (*const eval)(T &, T &) {};
public:
  segTree(std::vector<T> &v, T E, T (*func)(T &, T &)) : e(E), eval(func)
  {
    int siz = static_cast<int>(v.size());
    for (num = 1; num < siz; num <<= 1);
    dat = std::vector<T> (2 * num - 1, e);
    for (int i = 0; i < siz; ++i) dat[i + num - 1] = v[i];
    for (int i = num - 2; i >= 0; --i) dat[i] = eval(dat[i * 2 + 1], dat[i * 2 + 2]);
  }
  segTree(int n, T E, T (*func)(T &, T &)) : e(E), eval(func)
  {
    for (num = 1; num < n; num <<= 1);
    dat = std::vector<T> (2 * num - 1, e);
  }
  void update_a(int i, T val)
  {
    for (i += num - 1, dat[i] = val; i != 0;)
    {
      i = (i - 1) / 2;
      dat[i] = eval(dat[i * 2 + 1], dat[i * 2 + 2]);
    }
  }
  void update_r(int i, T val)
  {
    for (i += num - 1, dat[i] = eval(dat[i], val); i != 0;)
    {
      i = (i - 1) / 2;
      dat[i] = eval(dat[i * 2 + 1], dat[i * 2 + 2]);
    }
  }
  T getval(int left, int right)
  {
    left = std::max(0, left), right = std::min(num, right);
    T ansl = e, ansr = e;
    for (left += num - 1, right += num - 1; left < right; left >>= 1, right >>= 1)
    {
      if (!(left & 1)) ansl = eval(ansl, dat[left]);
      if (--right & 1) ansr = eval(dat[right], ansr);
    }
    return eval(ansl, ansr);
  }
  T getval(int id) {return dat[num - 1 + id];}
};

int main()
{
    int n, k, d;
    cin >> n >> k >> d;
    vector<pair<int, int>> a(n);
    vector<int> h(n);
    for (int i = 0; i < n; ++i)
    {
        cin >> h[i];
        a[i] = {h[i], i};
    }
    sort(a.begin(), a.end());
    vector<int> id(n);
    for (int i = 0; i < n; ++i) id[a[i].second] = i;
    segTree<long long> sg(n, 0, [](long long &a, long long &b) -> long long {return a + b;});
    segTree<int> sgc(n, 0, [](int &a, int &b) -> int {return a + b;});
    for (int i = 0; i < k - 1; ++i) sg.update_a(id[i], h[i]);
    for (int i = 0; i < k - 1; ++i) sgc.update_a(id[i], 1);
    auto cal = [&](long long x) -> long long
    {
        auto idl = lower_bound(a.begin(), a.end(), make_pair((int)x, 0)) - a.begin();
        auto idr = upper_bound(a.begin(), a.end(), make_pair((int)x + d, n + 1)) - a.begin();
        long long ret = sg.getval(idr, n) - sgc.getval(idr, n) * (long long)(x + d);
        // cout << sg.getval(idr, n) << ',' << idr << ',';
        // cout << x << ':';
        // cout << ret << endl;
        ret -= sg.getval(0, idl) - sgc.getval(0, idl) * (long long)x;
        return ret;
    };
    long long ans = (1LL << 60);
    for (int i = 0; i + k <= n; ++i)
    {
        sg.update_a(id[i + k - 1], h[i + k - 1]);
        sgc.update_a(id[i + k - 1], 1);
        long long l = 0, r = 1e9 - d;
        while (r - l > 2)
        {
            long long midl = ((long long)l + l + r) / 3;
            long long midr = ((long long)l + r + r) / 3;
            long long resl = cal(midl), resr = cal(midr);
            if (resl > resr) l = midl;
            else r = midr;
        }
        ans = min(ans, cal(l));
        ans = min(ans, cal(l + 1));
        ans = min(ans, cal(r));
        sg.update_a(id[i], 0);
        sgc.update_a(id[i], 0);
    }
    cout << ans << endl;
}