#include <bits/stdc++.h>
using namespace std;
const long long int MAX_N = 1 << 17;
using namespace std;
signed main() {
  long long int n, t, e;
  std::cin >> n >> e >> t;
  std::vector<long long int> x;
  for (long long int i = 0; i < n; i++) {
    long long int temp;
    std::cin >> temp;
    x.push_back(temp);
  }
  long long int sum = 0;
  sum += n * t + e;
  for (long long int i = 0; i < n - 1; i++) {
    long long int flag = 0;
    for (long long int k = 1; i + k < n; k++) {
      if ((x[i + k] - x[i]) * 2 < 2 * t) {
        flag = k;
      }
    }
    if (flag >= 1) {
      sum -= 2 * t - (x[i + flag] - x[i]) * 2;
    }
  }
  std::cout << sum << std::endl;
  return 0;
}
