#include <bits/stdc++.h>
using namespace std;
const int mod1 = 998244353, mod = 1e9 + 7;
const int MAXN = 100005, MAX_M = 200010;
long long n, x[MAXN], dp[MAXN], e, t;
void Solve() {
  cin >> n >> e >> t;
  for (long long i = 1; i <= n; i++) {
    cin >> x[i];
  }
  dp[0] = 0;
  for (long long i = 1; i <= n; i++) {
    dp[i] = 1e18;
    for (long long j = 0; j < i; j++)
      dp[i] = min(dp[i], dp[j] + max(2 * (x[i] - x[j + 1]), t));
  }
  cout << dp[n] + e;
}
signed main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long TC = 1;
  while (TC--) Solve();
  return 0;
}
