#include <bits/stdc++.h>
using namespace std;
template <typename P, typename Q>
ostream& operator<<(ostream& os, pair<P, Q> p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
int main(int argc, char* argv[]) {
  const int N = 100000 + 10;
  int n;
  long long int e, t;
  while (cin >> n >> e >> t) {
    long long int x[N];
    for (int i = 0; i < n; ++i) {
      cin >> x[i];
    }
    x[n] = e;
    long long int dp[N];
    fill(dp, dp + N, 1LL << 60);
    dp[0] = 0;
    for (int i = 0; i < n; ++i) {
      for (int j = i + 1; j <= n; ++j) {
        long long int cost = max(t, 2 * (x[j - 1] - x[i]));
        dp[j] = min(dp[j], dp[i] + cost);
      }
    }
    cout << dp[n] + e << endl;
  }
  return 0;
}
