#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <functional>
#include <cmath>
#include <string>
#include <queue>
#include <map>
#include <bitset>
#include <set>
#include <stack>
#include <numeric>
#include <unordered_map>
#include <random>

using namespace std;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vd = vector<double>;
using vs = vector<string>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<double, double>;
using vpii = vector<pii>;
using vpll = vector<pll>;
using vpdd = vector<pdd>;
const int inf = (1 << 30) - 1;
const ll INF = 1LL << 60;
//const int MOD = 1000000007;
const int MOD = 998244353;


int main() {
	ll n, d, t;
	cin >> n >> d >> t;
	vi x(n);
	map<int, vi> mp;
	for (int i = 0; i < n; i++) {
		cin >> x[i];
		int m = x[i] % d;
		if (m < 0) m += d;
		mp[m].push_back(x[i]);
	}
	
	ll ans = 0;
	for (auto& [k, v] : mp) {
		int sz = v.size();
		sort(v.begin(), v.end());
		ans += sz;
		ans += t * 2;

		for (int i = 0; i < sz - 1; i++) {
			int diff = v[i + 1] - v[i];
			ll tm = (diff + d * 2 - 1) / (d * 2) - 1;
			ans += min(tm, t) * 2;
			if (tm < t && (diff / d) % 2 == 0) ans++;
		}

	}
	cout << ans << endl;


	return 0;
}