#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <queue>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef unsigned long long ULL;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(auto i: c)
#define SORT(c) sort((c).begin(),(c).end())

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()

const double EPS = 1e-10;
const double PI  = acos(-1.0);

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;


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

	int N, D, T;
	cin >> N >> D >> T;

	vector<pair<LL, LL>> V(N);
	REP(i, N){
		LL tmp;
		cin >> tmp;
		V[i] = MP(tmp - T * D, tmp + T * D);
	}

	function<void(int, int)> f = [&](int a, int b){
		if((V[a].first % D != V[b].first % D) && (V[a].second % D != V[b].second % D)) return;
		if((V[a].first == 0 && V[a].second == 0) || (V[b].first == 0 && V[b].second == 0)) return;
		if(V[a].first <= V[b].second || V[a].second <= V[b].first){
			V[a].first = min(V[a].first, V[b].first);
			V[a].second = max(V[a].second, V[b].second);
			V[b] = MP(0, 0);
		}
	};

	REP(i, N - 1) FOR(j, i + 1, N){
		f(i, j);
	}

	LL ret = 0;
	for(auto i: V){
		if(i.first == 0 && i.second == 0) continue;
		ret += (i.second - i.first + 1) / D + 1;
		//cout << i.first << " " << i.second << endl;
	}

	cout << ret << endl;

	return 0;
}