#include <bits/stdc++.h>
using namespace std;
long long n, e, t, a[100010], dp[100010];
signed main() {
  ios::sync_with_stdio(false);
  cin >> n >> e >> t;
  for (long long i = 1; i <= n; i++) cin >> a[i];
  for (long long i = 1; i <= n; i++) {
    dp[i] = 1000000000000000007ll;
    for (long long j = 0; j < i; j++) {
      dp[i] = min(dp[i], dp[j] + max(t, 2 * (a[i] - a[j + 1])));
    }
  }
  cout << dp[n] + e << endl;
  return 0;
}
