#include <bits/stdc++.h>
using namespace std;
void solve();
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed;
  cout.precision(20);
  solve();
  return 0;
}
template <typename T>
void chmin(T& a, T b) {
  if (a > b) a = b;
}
template <typename T>
void chmax(T& a, T b) {
  if (a < b) a = b;
}
template <typename T>
void MACRO_rdv2_Init(int n, T& t) {
  t.resize(n);
}
template <typename First, typename... Rest>
void MACRO_rdv2_Init(int n, First& first, Rest&... rest) {
  first.resize(n);
  MACRO_rdv2_Init(n, rest...);
}
template <typename T>
void MACRO_rdv2_Scan(int p, T& t) {
  std::cin >> t[p];
}
template <typename First, typename... Rest>
void MACRO_rdv2_Scan(int p, First& first, Rest&... rest) {
  std::cin >> first[p];
  MACRO_rdv2_Scan(p, rest...);
}
template <typename T>
void wrv(const vector<T>& v) {
  for (int(__ii) = (0); (__ii) < (((int)v.size())); ++(__ii)) {
    if (__ii) cout << ' ';
    cout << v[__ii];
  }
  cout << '\n';
}
template <typename T>
void wrm(const vector<vector<T>>& v) {
  for (int(__ii) = (0); (__ii) < (((int)v.size())); ++(__ii)) {
    for (int(__jj) = (0); (__jj) < (v[__ii].size()); ++(__jj)) {
      if (__jj) cout << ' ';
      cout << v[__ii][__jj];
    }
    cout << '\n';
  }
}
template <typename T>
void sc(T& x) {
  cin >> x;
}
template <typename Head, typename... Tail>
void sc(Head& head, Tail&... tail) {
  cin >> head;
  sc(tail...);
}
template <typename T>
void wr(const T& x) {
  cout << x << '\n';
}
template <typename Head, typename... Tail>
void wr(const Head& head, const Tail&... tail) {
  cout << head << ' ';
  wr(tail...);
}
template <typename T>
void wrf(const T& x) {
  cout << x << endl;
}
template <typename Head, typename... Tail>
void wrf(const Head& head, const Tail&... tail) {
  cout << head << ' ';
  wrf(tail...);
}
template <typename T>
void debug_out(const T& x) {
  cerr << x << '\n';
}
template <typename Head, typename... Tail>
void debug_out(const Head& head, const Tail&... tail) {
  cerr << head << ' ';
  debug_out(tail...);
}
template <typename... T>
void err(const T&... cod) {
  wr(cod...);
  exit(0);
}
void solve() {
  int n, x, k;
  sc(n, x, k);
  vector<int> a(n);
  for (int(__ii) = (0); (__ii) < (n); ++(__ii)) cin >> a[__ii];
  sort(a.begin(), a.end());
  map<int, int> cnt, ans_ele;
  for (int(i) = (0); (i) < (n); ++(i)) {
    ++cnt[a[i]];
    if (cnt[a[i]] == 1) {
      int low = i - 1, high = n;
      while (low + 1 < high) {
        int mid = (low + high) / 2;
        if (a[mid] / x - (a[i] - 1) / x < k)
          low = mid;
        else
          high = mid;
      }
      int flow = low;
      high = n;
      while (low + 1 < high) {
        int mid = (low + high) / 2;
        if (a[mid] / x - (a[i] - 1) / x == k)
          low = mid;
        else
          high = mid;
      }
      ans_ele[a[i]] += low - flow;
    }
  }
  long long ans = 0;
  for (auto p : ans_ele) {
    ans += 1LL * p.second * cnt[p.first];
  }
  wr(ans);
}
