#include <iostream>
#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <algorithm>
#include <functional>
#include <limits.h>
#include <bitset>

#include <tuple>
#include <unordered_map>

#define mp make_pair
#define mt make_tuple
#define pb push_back
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;

const int INF = 1 << 29;
const double EPS = 1e-9;

const int dx[] = {1, 0, -1, 0}, dy[] = {0, -1, 0, 1};
ll N, D, T;
vector<ll> pos;
int main() {
  cin >> N >> D >> T;
  pos.resize(N);
  ll res = 0;
  for (int i = 0; i < N; i++) {
    cin >> pos[i];
  }
  sort(pos.begin(), pos.end());
  for (int i = 0; i < N; i++) {
    ll pleft, pright;
    pleft = pos[i] - D * T;
    pright = pos[i] + D * T;
    bool ok = false;
    for (int j = i + 1; j < N; j++) {
      ll qleft;
      qleft = pos[j] - D * T;
      ll dist = pos[j] - pos[i];
      if (pright >= qleft) {

        if (dist % D == 0) {
          ok = true;
          res += dist / D;
          break;
        }
      } else {
        if (dist % D == 0) {
          ok = true;
          res += (T + 1);
          break;
        }
      }
    }
    if (!ok) {
      res += (T + 1);
    }
  }
  // cout << res << endl;
  reverse(pos.begin(), pos.end());
  for (int i = 0; i < N; i++) {
    ll pleft, pright;
    // cout << " res = " << res << endl;
    pleft = pos[i] - D * T;
    // pright = pos[i] + D * T;
    bool ok = false;
    for (int j = i + 1; j < N; j++) {
      ll qright;
      qright = pos[j] + D * T;
      ll dist = abs(pos[j] - pos[i]);
      if (pleft <= qright) {
        if (dist % D == 0) {
          ok = true;
          // res += dist / D;
          break;
        }
      } else {
        if (dist % D == 0) {
          ok = true;
          res += (T);
          break;
        }
      }
    }
    if (!ok) {
      res += (T);
    }
  }

  cout << res << endl;
  return 0;
}