#include <bits/stdc++.h>
using namespace std;
static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
void solve() {
  long long n, e, t;
  cin >> n >> e >> t;
  assert(n <= 2000);
  vector<long long> x(n);
  for (int i = 0; i < n; i++) cin >> x[i];
  vector<long long> dp(n, INFL);
  dp[0] = t;
  for (int i = 1; i < n; i++) {
    for (int j = 0; j < i; j++)
      dp[i] = min(dp[i], dp[j] + max(t, 2 * (x[i] - x[j + 1])));
    dp[i] = min(dp[i], max(t, 2 * (x[i] - x[0])));
  }
  cout << dp[n - 1] + e << endl;
  return;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}
