#include <bits/stdc++.h>
using namespace std;
const int SIZE = 100001;
int N;
long E, T;
long x[SIZE];
int main(void) {
  cin >> N >> E >> T;
  for (int i = 1; i <= N; i++) {
    cin >> x[i];
  }
  long dp[SIZE];
  dp[0] = 0;
  for (int i = 1; i <= N; i++) {
    dp[i] = LONG_MAX;
    for (int j = 1; j <= i; j++) {
      dp[i] = min(dp[i], dp[j - 1] + max(T, (x[i] - x[j]) * 2));
    }
  }
  cout << dp[N] + E << endl;
  return 0;
}
