#include <bits/stdc++.h>
using namespace std;
const long long INF = 10000000000000000;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  long long n, e, t;
  cin >> n >> e >> t;
  vector<long long> x(n);
  for (int i = 0; i < n; i++) cin >> x[i];
  long long ans = e;
  vector<long long> dp(n + 1, INF);
  dp[0] = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < i; j++) {
      dp[i] = min(dp[i], dp[j] + max(t, (x[i - 1] - x[j]) * 2));
    }
  }
  ans += dp[n];
  cout << ans << endl;
  return 0;
}
