#include <bits/stdc++.h>
using namespace std;
template <typename T>
class segtree {
 private:
  int n, sz, h;
  vector<T> node, lazy_update, lazy_add;
  vector<bool> lazyFlag;

 public:
  segtree(const vector<T>& v) : n(1), sz((int)v.size()), h(0) {
    while (n < sz) n *= 2, h++;
    node.resize(2 * n, numeric_limits<T>::max());
    lazy_update.resize(2 * n, 0);
    lazyFlag.resize(2 * n, false);
    lazy_add.resize(2 * n, 0);
    for (int i = 0; i < sz; i++) node[i + n] = v[i];
    for (int i = n - 1; i >= 1; i--)
      node[i] = min(node[2 * i], node[2 * i + 1]);
  }
  void eval(int k) {
    if (lazyFlag[k]) {
      lazy_update[k] += lazy_add[k];
      node[k] = lazy_update[k];
      if (k < n) {
        lazy_add[2 * k] = lazy_add[2 * k + 1] = 0;
        lazy_update[2 * k] = lazy_update[2 * k + 1] = lazy_update[k];
        lazyFlag[2 * k] = lazyFlag[2 * k + 1] = true;
      }
      lazy_add[k] = 0, lazyFlag[k] = false;
    } else if (lazy_add[k] != 0) {
      node[k] += lazy_add[k];
      if (k < n) {
        lazy_add[2 * k] += lazy_add[k];
        lazy_add[2 * k + 1] += lazy_add[k];
      }
      lazy_add[k] = 0;
    }
  }
  void update(int a, int b, T x, int k = 1, int l = 0, int r = -1) {
    if (r < 0) r = n;
    eval(k);
    if (b <= l || r <= a) return;
    if (a <= l && r <= b) {
      lazy_add[k] = 0;
      lazy_update[k] = x;
      lazyFlag[k] = true;
      eval(k);
    } else {
      update(a, b, x, 2 * k, l, (l + r) / 2);
      update(a, b, x, 2 * k + 1, (l + r) / 2, r);
      node[k] = min(node[2 * k], node[2 * k + 1]);
    }
  }
  void add(int a, int b, T x, int k = 1, int l = 0, int r = -1) {
    if (r < 0) r = n;
    eval(k);
    if (b <= l || r <= a) return;
    if (a <= l && r <= b) {
      lazy_add[k] += x;
      eval(k);
    } else {
      add(a, b, x, 2 * k, l, (l + r) / 2);
      add(a, b, x, 2 * k + 1, (l + r) / 2, r);
      node[k] = min(node[2 * k], node[2 * k + 1]);
    }
  }
  T query(int a, int b) {
    a += n, b += n - 1;
    for (int i = h; i > 0; i--) eval(a >> i), eval(b >> i);
    b++;
    T res1 = numeric_limits<T>::max(), res2 = numeric_limits<T>::max();
    while (a < b) {
      if (a & 1) eval(a), res1 = min(res1, node[a++]);
      if (b & 1) eval(--b), res2 = min(res2, node[b]);
      a >>= 1, b >>= 1;
    }
    return min(res1, res2);
  }
  void print() {
    for (int i = 0; i < sz; i++) {
      cout << query(i, i + 1) << " ";
    }
    cout << endl;
  }
};
int main() {
  long long n, e, t;
  cin >> n >> e >> t;
  if (n >= 2001) return 0;
  vector<long long> a(n + 1);
  a[0] = 0;
  for (int i = 0; i < (int)(n); ++i) {
    cin >> a[i + 1];
  }
  a.push_back(e);
  n += 2;
  vector<long long> dp(n, 1LL << 60);
  segtree<long long> sg(dp);
  int p = 0;
  for (int i = 0; i < (int)(n - 1); ++i) {
    if (i == 0) {
      sg.update(0, 1, a[1] - a[0]);
      continue;
    }
    long long k = sg.query(0, i);
    sg.update(i, i + 1, k + t);
    sg.add(0, p, 3 * (a[i + 1] - a[i]));
    sg.add(p, i + 1, (a[i + 1] - a[i]));
    while (1) {
      if (3 * (a[i + 1] - a[p + 1]) > t + (a[i + 1] - a[p + 1])) {
        sg.add(p, p + 1, -(t + (a[i + 1] - a[p + 1])));
        sg.add(p, p + 1, 3 * (a[i + 1] - a[p + 1]));
        p++;
      } else {
        break;
      }
    }
    cerr << p << endl;
  }
  cout << sg.query(n - 2, n - 1) << endl;
  return 0;
}
