#include <bits/stdc++.h>
using namespace std;
int N, E, T;
int x[101010];
long long dp[101010];
int main() {
  cin >> N >> E >> T;
  for (int i = 0; i < N; i++) scanf("%d", &x[i + 1]);
  dp[0] = 0;
  for (int i = 1; i < N + 1; i++) {
    dp[i] = 1LL << 60;
    for (int j = 0; j < i; j++)
      dp[i] = min(dp[i], dp[j] + max(2 * (x[i] - x[j + 1]), T));
  }
  cout << dp[N] + E << endl;
}
