#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
long long N, E, T, ans;
long long x[100005];
int main() {
  cin >> N >> E >> T;
  ans = E;
  for (long long i = 0; i < N; i++) {
    cin >> x[i];
  }
  for (long long i = 0; i < N; i++) {
    for (long long j = i + 1; j < N; j++) {
      if (x[j] - x[i] > T) {
        i = j;
        break;
      }
      if (j == N - 1) {
        i = j;
      }
    }
    ans += T * 2;
  }
  cout << ans << endl;
  return 0;
}
