#include <bits/stdc++.h>
using namespace std;
const int MOD = (int)1e9 + 7;
const int INF = (int)1e9;
const long long LINF = (long long)1e18;
const long double PI = acos((long double)-1);
const long double EPS = 1e-9;
inline long long gcd(long long a, long long b) {
  long long r;
  while (b) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
inline long long fpow(long long n, long long k, int p = MOD) {
  long long r = 1;
  for (; k; k >>= 1) {
    if (k & 1) r = r * n % p;
    n = n * n % p;
  }
  return r;
}
template <class T>
inline int chkmin(T& a, const T& val) {
  return val < a ? a = val, 1 : 0;
}
template <class T>
inline int chkmax(T& a, const T& val) {
  return a < val ? a = val, 1 : 0;
}
template <class T>
inline T isqrt(T k) {
  T r = sqrt(k) + 1;
  while (r * r > k) r--;
  return r;
}
template <class T>
inline T icbrt(T k) {
  T r = cbrt(k) + 1;
  while (r * r * r > k) r--;
  return r;
}
inline void addmod(int& a, int val, int p = MOD) {
  if ((a = (a + val)) >= p) a -= p;
}
inline void submod(int& a, int val, int p = MOD) {
  if ((a = (a - val)) < 0) a += p;
}
inline int mult(int a, int b, int p = MOD) { return (long long)a * b % p; }
inline int inv(int a, int p = MOD) { return fpow(a, p - 2, p); }
const int maxn = 100000 + 10;
int n, e, t;
int x[maxn];
int nxt[maxn];
long long f[maxn];
long long rmq[2][maxn << 1];
void upd(int k, int p, long long val) {
  for (rmq[k][p += maxn] = val; p > 1;)
    p >>= 1, rmq[k][p] = min(rmq[k][p << 1], rmq[k][p << 1 | 1]);
}
long long query(int k, int l, int r) {
  long long res = LINF;
  for (l += maxn, r += maxn + 1; l < r; l >>= 1, r >>= 1) {
    if (l & 1) res = min(res, rmq[k][l++]);
    if (r & 1) res = min(res, rmq[k][--r]);
  }
  return res;
}
void solve() {
  cin >> n >> e >> t;
  for (int i = (0); i < (n); i++) cin >> x[i];
  x[n] = e;
  for (int i = 0; i < (maxn << 1); i++) {
    rmq[0][i] = rmq[1][i] = LINF;
  }
  int ptr = 0;
  for (int i = (0); i < (n); i++) {
    while (ptr < n - 1 && 2 * (x[ptr + 1] - x[i]) <= t) ptr++;
    nxt[i] = ptr;
  }
  upd(0, n, f[n] + x[n] + t);
  upd(1, n, f[n] + 2 * x[n - 1] + x[n]);
  for (int i = (n)-1; i >= (0); i--) {
    int ix = nxt[i];
    f[i] = query(0, i + 1, ix + 1) - x[i];
    chkmin(f[i], query(1, ix + 2, n) - 3 * x[i]);
    if (i) {
      upd(0, i, f[i] + x[i] + t);
      upd(1, i, f[i] + 2 * x[i - 1] + x[i]);
    }
  }
  cout << f[0] + x[0] << "\n";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  solve();
  return 0;
}
