#include <bits/stdc++.h>
#define FOR(v, a, b) for(int v = (int)(a); v < (int)(b); ++v)
#define FORE(v, a, b) for(int v = (int)(a); v <= (int)(b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define RS resize
#define CLR clear
#define PB push_back
#define PF push_front
#define ALL(x) (x).begin(), (x).end()
#define C complex
#define CI complex< int >
#define CD complex< double >
using namespace std;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int n, d, t, x;
	long int c = 0;
	map< int, vector< int > > mp;
	
	cin >> n >> d >> t;
	REP(i, n){
		cin >> x;
		
		int mod;
		if(x>=0 || x % d == 0) mod = x % d;
		else mod = d - ((-x) % d);
				
		if(mp.find(mod) != mp.end()){
			mp[mod].PB(x);
		}else{
			vector< int > temp;
			mp[mod] = temp;
			mp[mod].PB(x);
		}
	}
	
	for(map< int, vector< int > >::iterator it = mp.begin(); it != mp.end(); ++it){
		vector< int > v = it->second;
		
		REP(i, v.size()) v[i] = floor(1.0 * v[i] / d);
		
		sort(ALL(v));
		
		int cnt = t * 2 + 1;
		FOR(i, 1, v.size()){
			if(v[i-1] + t < v[i] - t){
				cnt += 2 * t + 1;
			}else{
				cnt += (v[i] - v[i-1]);
			}
		}
		c += cnt;
	}
	
	cout << c << endl;
	
	return 0;
}