#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1e9 + 7;
const int N = 8001;
long long int dp[N];
const long long int inf = 1e16;
int main(void) {
  int n;
  long long int e, t;
  cin >> n >> e >> t;
  assert(n < N);
  vector<long long int> x(n + 1);
  x[0] = 0;
  for (int i = (int)(0); i < (int)(n); i++) {
    cin >> x[i + 1];
  }
  dp[0] = 0;
  for (int i = (int)(0); i < (int)(n); i++) {
    long long int ret = inf;
    for (int j = (int)(0); j < (int)(i + 1); j++) {
      ret = min(ret, dp[j] + max(t, 2 * (x[i + 1] - x[j + 1])));
    }
    dp[i + 1] = ret;
  }
  cout << dp[n] + e << endl;
}
