#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1e9 + 7;
bool IsPowerOfTwo(long long int x) { return (x != 0) && ((x & (x - 1)) == 0); }
long long int poer(long long int a, long long int b) {
  long long int rs = 1;
  while (b > 0) {
    if (b & 1) rs *= a;
    a *= a;
    b /= 2;
  }
  return rs;
}
long long int mod_poer(long long int a, long long int b, long long int mo) {
  long long int rs = 1;
  while (b > 0) {
    if (b & 1) rs = (rs * a) % mo;
    a = (a * a) % mo;
    b /= 2;
  }
  return rs % mo;
}
long long int d, x, y;
void ext_euclid(long long int a, long long int b) {
  if (b == 0) {
    d = a;
    x = 1;
    y = 0;
  } else {
    ext_euclid(b, a % b);
    long long int temp = x;
    x = y;
    y = temp - (a / b) * y;
  }
}
long long int mod_inverse1(long long int a, long long int m) {
  ext_euclid(a, m);
  return (x % m + m) % m;
}
long long int mod_inverse2(long long int a, long long int m) {
  return mod_poer(a, m - 2, m);
}
long long int gcd(long long int a, long long int b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
long long int fact[200005];
void fac() {
  fact[1] = fact[0] = 1;
  for (long long int i = 2; i <= 200005; ++i) {
    fact[i] = ((fact[i - 1] % mod) * i) % mod;
  }
}
long long int combi(long long int a, long long int b) {
  if (b > a) return 0;
  if (b == a)
    return 1;
  else {
    long long int x = mod_poer(fact[b], mod - 2, mod) % mod;
    long long int y = mod_poer(fact[a - b], mod - 2, mod) % mod;
    return ((((fact[a]) * x) % mod) * y) % mod;
  }
}
long long int n, xi, k, ans, a[100005], res;
map<long long int, long long int> cnt;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> xi >> k;
  for (long long int i = 1; i <= n; ++i) cin >> a[i];
  sort(a + 1, a + n + 1);
  for (long long int i = 1; i <= n; ++i) {
    cnt[a[i]]++;
    long long int ansL = 0, ansR = 0;
    long long int R = (a[i] / xi) * xi - (k - 1) * xi;
    long long int L = R - xi;
    long long int l = 1, r = i;
    while (l <= r) {
      long long int mid = l + r >> 1;
      if (a[mid] <= R)
        ansR = mid, l = mid + 1;
      else
        r = mid - 1;
    }
    l = 1, r = i;
    while (l <= r) {
      long long int mid = l + r >> 1;
      if (a[mid] <= L)
        ansL = mid, l = mid + 1;
      else
        r = mid - 1;
    }
    res += ansR - ansL;
    if (R >= a[i] && L < a[i]) res += cnt[a[i]], res--;
  }
  cout << res << "\n";
  return 0;
}
