#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <algorithm>

using namespace std;

int main() {
	int n;
	long long d, t;
	cin >> n >> d >> t;
	vector<long long> x(n);
	for (int i = 0; i < n; ++i) {
		cin >> x[i];
	}
	map<long long, set<long long> > positions;
	for (int i = 0; i < n; ++i) {
		positions[(0x80000000LL + x[i]) % d].insert(x[i]);
	}
	long long result = 0LL;
	for (map<long long, set<long long> >::const_iterator it = positions.begin();
		it != positions.end();
		++it) {
		vector<long long> distances;
		set<long long>::const_iterator itSet = it->second.begin();
		for (;;) {
			set<long long>::const_iterator itNext = itSet;
			++itNext;
			if (itNext == it->second.end()) {
				break;
			}
			distances.push_back(*itNext - *itSet);
			itSet = itNext;
		}
		sort(distances.begin(), distances.end());
		size_t amebaCount = it->second.size();
		result += amebaCount;
		long long lastJoining = 0;
		for (size_t i = 0; i < distances.size(); ++i) {
			long long joining = min(t, distances[i] / (2 * d));
			result += 2 * amebaCount * (joining - lastJoining);
			if (joining == distances[i] / (2 * d)) {
				--result;
			}
			lastJoining = joining;
			if (lastJoining == t) {
				break;
			}
			--amebaCount;
		}
		if (lastJoining < t) {
			result += 2 * amebaCount * (t - lastJoining);
		}
	}
	cout << result << endl;
	return 0;
}