#include <bits/stdc++.h>
using namespace std;
class Point {
 public:
  double x, y;
  Point(double x = 0, double y = 0) : x(x), y(y) {}
  Point operator+(Point p) { return Point(x + p.x, y + p.y); }
  Point operator-(Point p) { return Point(x - p.x, y - p.y); }
  Point operator*(double a) { return Point(x * a, y * a); }
  Point operator/(double a) { return Point(x / a, y / a); }
  double absv() { return sqrt(norm()); }
  double norm() { return x * x + y * y; }
  bool operator<(const Point &p) const { return x != p.x ? x < p.x : y < p.y; }
  bool operator==(const Point &p) const {
    return fabs(x - p.x) < (1e-10) && fabs(y - p.y) < (1e-10);
  }
};
struct Segment {
  Point p1, p2;
};
double hen(Point a) {
  if (fabs(a.x) < (1e-10) && a.y > 0)
    return acos(0);
  else if (fabs(a.x) < (1e-10) && a.y < 0)
    return 3 * acos(0);
  else if (fabs(a.y) < (1e-10) && a.x < 0)
    return 2 * acos(0);
  else if (fabs(a.y) < (1e-10) && a.x > 0)
    return 0.0;
  else if (a.y > 0)
    return acos(a.x / a.absv());
  else
    return 2 * acos(0) + acos(-a.x / a.absv());
}
double dot(Point a, Point b) { return a.x * b.x + a.y * b.y; }
double cross(Point a, Point b) { return a.x * b.y - a.y * b.x; }
long long n, e, t;
long long x[2020];
long long dp[2010] = {0};
vector<long long> ve[4000005];
signed main() {
  cin >> n >> e >> t;
  if (n > 2010) {
    return 0;
  }
  for (long long i = 1; i <= n; i++) cin >> x[i];
  x[0] = 0;
  dp[0] = 0;
  for (long long i = 1; i <= n; i++) {
    long long u = 100000000000000000ll;
    for (long long j = 0; j < i; j++) {
      u = min(u, dp[j] + max(t, 2 * (x[i] - x[j + 1])));
    }
    dp[i] = u;
  }
  cout << dp[n] + e << endl;
  return 0;
  return 0;
}
