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

using namespace std;

const long long INF = 1e18;

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

	cin >> n >> d >> t;
	map<int,  vector<long long> > aaa;


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

	long long ans = 0;
	for (auto it = aaa.begin(); it != aaa.end(); it++) {
		long long start = -INF;
		long long prev = it->second[0];
		ans += t;
		for (int i = 0; i < it->second.size(); i++) {
			if (start == -INF) {
				start = it->second[i];
				prev = start;
			}
			if (it->second[i] - prev > d * t * 2) {
				ans += (prev - start) / d + 1;
				ans += t * 2;
				start = -INF;
			}
			prev = it->second[i];
		}
		if (start != -INF) {
			ans += (prev - start) / d + 1;
		}
		ans += t;
	}

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