#include <bits/stdc++.h>
using namespace std;
int x[114514];
long long dp[114514];
int main() {
  int n, e, t, now = 0;
  long long out = 0;
  scanf("%d %d %d", &n, &e, &t);
  for (int i = 0; i < n; i++) scanf("%d", &x[i]);
  x[n] = 2001001001;
  for (int i = 0; i < n + 10; i++) dp[i] = 1145141919810893LL;
  dp[0] = 0;
  for (int i = 0; i < n; i++)
    for (int j = i + 1; j < n + 1; j++) {
      dp[j] = min(dp[j], dp[i] + max(t, 2 * (x[j - 1] - x[i])));
    }
  out = e + dp[n];
  cout << out << endl;
}
