#include <bits/stdc++.h>
using namespace std;
const int Imx = 2147483647;
const long long Lbig = 2e18;
const int mod = 1e9 + 7;
struct fastio {
  char s[100000];
  int it, len;
  fastio() { it = len = 0; }
  inline char get() {
    if (it < len) return s[it++];
    it = 0;
    len = fread(s, 1, 100000, stdin);
    if (len == 0)
      return EOF;
    else
      return s[it++];
  }
  bool notend() {
    char c = get();
    while (c == ' ' || c == '\n') c = get();
    if (it > 0) it--;
    return c != EOF;
  }
} _buff;
inline long long getnum() {
  long long r = 0;
  bool ng = 0;
  char c;
  c = _buff.get();
  while (c != '-' && (c < '0' || c > '9')) c = _buff.get();
  if (c == '-') ng = 1, c = _buff.get();
  while (c >= '0' && c <= '9') r = r * 10 + c - '0', c = _buff.get();
  return ng ? -r : r;
}
template <class T>
inline void putnum(T x) {
  if (x < 0) putchar('-'), x = -x;
  register short a[20] = {}, sz = 0;
  while (x) a[sz++] = x % 10, x /= 10;
  if (sz == 0) putchar('0');
  for (int i = sz - 1; i >= 0; i--) putchar('0' + a[i]);
}
inline char getreal() {
  char c = _buff.get();
  while (c == ' ' || c == '\n') c = _buff.get();
  return c;
}
int n;
long long T, E, pos[100111];
long long dp[100111];
pair<long long, int> q[100111];
int qb, qe;
void add(int id) {
  while (qe > qb && q[qe - 1].first <= dp[id]) qe--;
  q[qe++] = make_pair(dp[id], id);
}
void del(int id) {
  if (qb < qe && q[qb].second == id) qb++;
}
int main() {
  int tmp;
  n = getnum(), tmp = getnum(), T = getnum();
  for (int i = 1; i <= n; i++) pos[i] = getnum(), pos[i] *= 2;
  long long mn = 1ll * mod * mod;
  int it = -1;
  add(0);
  for (int i = 1; i <= n; i++) {
    while (pos[i] - pos[it + 2] > T) {
      it++;
      del(it);
      mn = min(mn, dp[it] - pos[it + 1]);
    }
    dp[i] = mn + pos[i];
    if (qb < qe) dp[i] = min(dp[i], q[qb].first + T);
    add(i);
  }
  cout << dp[n] + tmp << endl;
  return 0;
}
