#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))

#define MOD 1000000007

int main(){
  long long N,D,T;
  cin>>N>>D>>T;
  vector<int> v;
  rep(i,0,N){
    int a;
    cin>>a;
    v.pb(a+1000000000);
  }
  set<int> se;
  rep(i,0,v.sz){
    se.insert(v[i]%D);
  }
  vector<int> vd(all(se));
  long long ans=0LL;
  rep(i,0,vd.sz){
    vector<int> v1;
    rep(j,0,v.sz){
      if(v[j]%D==vd[i]){
        v1.pb(v[j]);
      }
    }
    sort(all(v1));
    rep(j,0,v1.sz-1){
      long long p1 = v1[j];
      long long p2 = v1[j+1];
      long long d1 = p1+D*T;
      long long d2 = p2-D*T;
      if(d2<=d1){
        ans += (p2-p1)/D-1;
      }
      else{
        ans += T*2;
      }
    }
    ans += T*2;
  }
  cout << ans+v.sz << endl;
  return 0;
}