#define _CRT_SECURE_NO_WARNINGS
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <bitset>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii;
typedef long long ll; typedef vector<long long> vl; typedef pair<long long,long long> pll; typedef vector<pair<long long,long long> > vpll;
typedef vector<string> vs; typedef long double ld;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N, D, T;
	scanf("%d%d%d", &N, &D, &T);
	map<int,vector<long long> > poses;
	rep(i, N) {
		int X;
		scanf("%d", &X);
		long long XX = X + 10000000000000LL;
		int m = XX % D;
		poses[m].push_back(XX / D);
	}
	long long ans = 0;
	each(ps, poses) {
		vector<long long> &v = ps->second;
		sort(all(v));
		vector<long long> xs;
		vector<pair<long long, long long> > intervals;
//		cerr << ps->first << ": ";
		each(x, v) {
			long long L = (long long)*x - T;
			long long R = (long long)*x + T;
			xs.push_back(L-1);
			xs.push_back(L);
			xs.push_back(L+1);
			xs.push_back(R-1);
			xs.push_back(R);
			xs.push_back(R+1);
			intervals.push_back(mp(L, R));
		}
//		cerr << endl;
		sort(all(xs));
		xs.erase(unique(all(xs)), xs.end());
		int X = xs.size();
		vector<int> cnt(X+1);
		each(p, intervals) {
			int L = lower_bound(all(xs), p->first) - xs.begin();
			int R = lower_bound(all(xs), p->second) - xs.begin();
			++ cnt[L];
			-- cnt[R+1];
		}
		rer(i, 1, X) cnt[i] += cnt[i-1];
		rep(i, X) if(cnt[i] > 0)
			ans += xs[i+1] - xs[i];
	}
	printf("%lld\n", ans);
	return 0;
}