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

using namespace std;

const long long INF = 1e18;

template <class T>
void show(T &a, string sep = " ") {
	for (auto it = a.begin(); it != a.end(); it++) {
		cout << *it << sep;
	}
	cout << endl;
}

int main() {
	long long n, d, t;

	cin >> n >> d >> t;
	map<int,  vector<long long> > aaa;
	vector<long long> x(n, 0);

	for (int i = 0; i < n; i++) {
		cin >> x[i];
	}
	sort(x.begin(), x.end());

	for (int i = 0; i < n; i++) {
		int idx = (x[i] + (int)1e9) % d;
		auto it = aaa.find(idx);
		if (it == aaa.end()) {
			aaa[idx] = vector<long long>(1, x[i]);
		} else {
			aaa[idx].push_back(x[i]);
		}
	}

	long long ans = 0;
	for (auto it = aaa.begin(); it != aaa.end(); it++) {
		// printf("%2d: ", it->first);
		// show(it->second);
		long long start = it->second[0];
		long long prev = start;
		ans += t;
		for (int i = 0; i < it->second.size(); i++) {
			// printf("%d now %lld prev %lld, start %lld,  ", i, it->second[i], prev, start);
			if (it->second[i] - prev > d * t * 2) {
				ans += (prev - start) / d + 1 + t + t;
				start = it->second[i];
			}
			// printf("ans %lld\n", ans);
			prev = it->second[i];
		}
		if (start != -INF) {
			ans += (prev - start) / d + 1;
		}
		ans += t;

		// printf("ans %lld\n", ans);
	}

	cout << ans << endl;
	return 0;
}