#include<bits/stdc++.h>
using namespace std;
#define inf INT_MAX
#define INF LLONG_MAX
#define ll long long
#define ull unsigned long long
#define M (int)(1e9+7)
#define P pair<int,int>
#define PLL pair<ll,ll>
#define FOR(i,m,n) for(int i=(int)m;i<(int)n;i++)
#define RFOR(i,m,n) for(int i=(int)m;i>=(int)n;i--)
#define rep(i,n) FOR(i,0,n)
#define rrep(i,n) RFOR(i,n,0)
#define all(a) a.begin(),a.end()
#define IN(a,n) rep(i,n){ cin>>a[i]; }
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265
#define F first
#define S second
#define PB push_back
#define EB emplace_back
#define int ll
#define vi vector<int>



signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n,d,t;
  cin>>n>>d>>t;

  vector<P> v;
  rep(i,n){
    int x;
    cin>>x;
    v.PB(P(x-t*d,x+t*d));
  }

  sort(all(v));

  vector<bool> b(n,false);

  rep(i,n){
    if(b[i]) continue;
    FOR(j,i+1,n){
      if(abs(v[i].F-v[j].F)%d==0&&v[i].S>=v[j].F){
        b[j]=true;
        v[i].S=v[j].S;
      }
    }
  }

  int ans=0;
  rep(i,n){
    if(!b[i]){
      ans+=1+(v[i].S-v[i].F)/d;
    }
  }

  cout<<ans<<endl;

}