#include <bits/stdc++.h>
using namespace std;
int main(){
  int N, D, T;
  cin >> N >> D >> T;
  vector<int> X(N);
  for (int i = 0; i < N; i++){
    cin >> X[i];
  }
  map<int, vector<int>> mp;
  for (int i = 0; i < N; i++){
    int r = X[i] % D;
    if (r < 0){
      r += D;
    }
    mp[r].push_back((X[i] - r) / D);
  }
  long long ans = 0;
  for (auto P : mp){
    int cnt = P.second.size();
    vector<int> p;
    for (int i = 0; i < cnt; i++){
      p.push_back(P.second[i] - T);
      p.push_back(P.second[i] + T + 1);
    }
    sort(p.begin(), p.end());
    p.erase(unique(p.begin(), p.end()), p.end());
    int cnt2 = p.size();
    vector<int> imos(cnt2 + 1, 0);
    for (int i = 0; i < cnt; i++){
      int L = lower_bound(p.begin(), p.end(), P.second[i] - T) - p.begin();
      int R = lower_bound(p.begin(), p.end(), P.second[i] + T + 1) - p.begin();
      imos[L]++;
      imos[R]--;
    }
    for (int i = 0; i < cnt2; i++){
      imos[i + 1] += imos[i];
    }
    for (int i = 0; i < cnt2 - 1; i++){
      if (imos[i] > 0){
        ans += p[i + 1] - p[i];
      }
    }
  }
  cout << ans << endl;
}