#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
const long long inf = 1e18;
int n;
long long E, t, a[N], dp[N];
int main() {
  cin >> n >> E >> t;
  for (int i = 1; i <= n; ++i) scanf("%lld", &a[i]);
  dp[0] = 0;
  for (int i = 1; i <= n; ++i) {
    dp[i] = inf;
    for (int j = 1; j <= i; ++j) {
      dp[i] = min(dp[i], dp[j - 1] + max(t, 2 * (a[i] - a[j])));
    }
  }
  printf("%lld\n", dp[n] + E);
  return 0;
}
