#include <bits/stdc++.h>
using namespace std;
namespace mine {
long long qread() {
  long long ans = 0, f = 1;
  char c = getchar();
  while (c < '0' or c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while ('0' <= c and c <= '9') ans = ans * 10 + c - '0', c = getchar();
  return ans * f;
}
void write(long long num) {
  if (num < 0) putchar('-'), num = -num;
  if (num >= 10) write(num / 10);
  putchar('0' + num % 10);
}
void write1(long long num) {
  write(num);
  putchar(' ');
}
void write2(long long num) {
  write(num);
  putchar('\n');
}
template <typename T>
void chmax(T &x, const T y) {
  x = (x > y ? x : y);
}
template <typename T>
void chmin(T &x, const T y) {
  x = (x < y ? x : y);
}
long long gcd(long long x, long long y) { return y ? gcd(y, x % y) : x; }
const int INF = 0x3f3f3f3f;
const int MOD = 998244353;
int mm(const int x) { return x >= MOD ? x - MOD : x; }
template <typename T>
void add(T &x, const int &y) {
  x = (x + y >= MOD ? x + y - MOD : x + y);
}
long long qpower(long long x, long long e, int mod = MOD) {
  long long ans = 1;
  (e >= 0);
  while (e) {
    if (e & 1) ans = ans * x % mod;
    x = x * x % mod;
    e >>= 1;
  }
  return ans;
}
long long invm(long long x) { return qpower(x, MOD - 2); }
const int N = 1e5 + 10;
long long f[N], a[N];
void main() {
  long long n = qread(), E = qread(), T = qread();
  for (int i = (1), I = (n); i <= I; i++) a[i] = qread();
  a[n + 1] = E;
  memset(f, 0x3f, sizeof f);
  f[0] = 0;
  for (int i = (1), I = (n + 1); i <= I; i++)
    for (int j = (0), I = (i - 1); j <= I; j++)
      chmin(f[i], f[j] + max(T, 2 * (a[i] - a[j + 1])));
  write(f[n + 1] + E);
}
};  // namespace mine
signed main() {
  srand(time(0));
  mine::main();
}
