#include <bits/stdc++.h>
using namespace std;

int main() {
  int N, D, T;
  cin >> N >> D >> T;
  map<int, vector<int>> MA;
  for (int x; cin >> x;) MA[(x % D + D) % D].push_back(x);
  int ans = 0;
  for (auto [a, X] : MA) {
    sort(X.begin(), X.end());
    int pre = INT_MIN;
    for (auto x : X) {
      int l = x - D * T;
      int r = x + D * T;
      if (l < pre) ans -= (pre - l) / D + 1;
      ans += T * 2 + 1;
      pre = r;
    }
  }
  cout << ans << "\n";
}