#include <bits/stdc++.h>
using namespace std;
unsigned long xor128() {
  static unsigned long x = time(NULL), y = 362436069, z = 521288629,
                       w = 88675123;
  unsigned long t = (x ^ (x << 11));
  x = y;
  y = z;
  z = w;
  return (w = (w ^ (w >> 19)) ^ (t ^ (t >> 8)));
}
double dot(complex<double> a, complex<double> b) {
  return a.real() * b.real() + a.imag() * b.imag();
}
double gyaku_dot(complex<double> a, complex<double> b) {
  return a.real() * b.imag() - a.imag() * b.real();
}
double leng(complex<double> a) {
  return sqrt(a.real() * a.real() + a.imag() * a.imag());
}
double angles(complex<double> a, complex<double> b) {
  double cosine = dot(a, b) / (leng(a) * leng(b));
  double sine = gyaku_dot(a, b) / (leng(a) * leng(b));
  double kaku = acos(min((double)1.0, max((double)-1.0, cosine)));
  if (sine <= 0) {
    kaku = 2 * 3.141592653589793 - kaku;
  }
  return kaku;
}
vector<int> convex_hull(vector<complex<double>> a) {
  vector<int> ans;
  double now_minnest = a[0].real();
  int now_itr = 0;
  for (long long i = 0; i < a.size(); ++i) {
    if (now_minnest > a[i].real()) {
      now_minnest = a[i].real();
      now_itr = i;
    }
  }
  ans.push_back(now_itr);
  complex<double> ba(0, 1);
  while (true) {
    int now_go = 0;
    double now_min = 0;
    double now_length = 0;
    int starter = ans[ans.size() - 1];
    for (int i = 0; i < a.size(); ++i) {
      if (i != starter) {
        double goa = angles(ba, a[i] - a[starter]);
        if (goa - now_min >= 1e-5 ||
            (abs(goa - now_min) <= 1e-5 &&
             (abs(a[i] - a[starter]) - now_length) >= 1e-5)) {
          now_min = goa;
          now_go = i;
          now_length = abs(a[i] - a[starter]);
        }
      }
    }
    if (now_go == ans[0]) break;
    ans.push_back(now_go);
    ba = complex<double>(a[now_go] - a[starter]);
  }
  return ans;
}
long long dp[200000];
int main() {
  long long n, e, t;
  cin >> n >> e >> t;
  vector<long long> inputs;
  inputs.push_back(0);
  for (long long i = 0; i < n; ++i) {
    long long a;
    cin >> a;
    inputs.push_back(a);
    dp[i + 1] = 1e18;
  }
  n++;
  dp[0] = 0;
  long long now_cost = 1e18;
  priority_queue<pair<long long, long long>, vector<pair<long long, long long>>,
                 greater<pair<long long, long long>>>
      next;
  next.push(make_pair(-inputs[1], 1));
  long long now_back = 0;
  for (long long i = 1; i < n; ++i) {
    while (2 * (inputs[i] - inputs[now_back + 1]) > t) {
      long long geko = -2 * inputs[now_back + 1] + dp[now_back];
      now_cost = min(now_cost, geko);
      now_back++;
    }
    dp[i] = min(dp[i], now_cost + 2 * inputs[i]);
    while (next.empty() == false &&
           2 * (inputs[i] - inputs[next.top().second]) > t) {
      next.pop();
    }
    if (next.empty() == false) {
      dp[i] = min(dp[i], next.top().first + inputs[i] + t);
    }
    if (i != n - 1) next.push(make_pair(dp[i] - 2 * inputs[i + 1], i + 1));
  }
  cout << dp[n - 1] + e << endl;
}
