#include <bits/stdc++.h>

#define REP(i, x, n) for(int i = x; i < (int)(n); i++)
#define rep(i, n) REP(i, 0, n)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define F first
#define S second
#define mp make_pair

using namespace std;

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

int main() {
  // ios_base::sync_with_stdio(false);
  ll N, D, T;
  cin >> N >> D >> T;
  vector<ll> x(N);
  rep(i, N) cin >> x[i];

  ll ans = 0;
  rep(i, N) {
    ll l1 = x[i] - D * T;
    ll r1 = x[i] + D * T;
    bool flg = true;
    rep(j, i) {
      if(abs(x[i] - x[j]) % D) continue;
      ll l2 = x[j] - D * T;
      ll r2 = x[j] + D * T;
      if(l2 <= l1 && r1 <= r2) {
        flg = false;
        break;
      }
      else if(l1 <= r2) {
        l1 = r2 + D;
      }
      else if(r1 >= l2) {
        r1 = l2 - D;
      }
      if(l1 > r1) {
        flg = false;
        break;
      }
    }
    if(flg) ans += (r1 - l1) / D + 1;
  }

  cout << ans << endl;
  
  return 0;
}