#include <bits/stdc++.h>
const long long INF = 10000000000000000;
using namespace std;
int main() {
  long long N, E, T;
  cin >> N >> E >> T;
  vector<long long> x(N);
  for (int i = 0; i < N; i++) cin >> x[i];
  vector<long long> dp(N + 1, INF);
  dp[0] = 0;
  for (int i = 0; i <= N; i++) {
    for (int j = 0; j < i; j++) {
      dp[i] = min(dp[i], dp[j] + max(T, 2 * (x[i - 1] - x[j])));
    }
  }
  cout << dp[N] + E << endl;
  return 0;
}
