#include <cstdio>
#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>
#include <numeric>
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
//constexpr long long MAX = 5100000;
constexpr long long INF = 1LL << 60;
constexpr int inf = 1000000007;
//constexpr long long mod = 1000000007LL;
//constexpr long long mod = 998244353LL;
const long double PI = acos((long double)(-1));

using namespace std;
typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;


int main()
{
    /*
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    */
	int n, D, T; scanf("%d %d %d", &n, &D, &T);
	vector<int> x(n); for (int i = 0; i < n; i++) scanf("%d", &x[i]);
	map<int, vector<int>> mp;
	for (int i = 0; i < n; i++) mp[(x[i] % D + D) % D].emplace_back(x[i]);
	ll res = 0;
	for (auto& p : mp) {
		auto& v = p.second;
		sort(v.begin(), v.end());
		for (int i = 0; i + 1 < v.size(); i++) {
			int t = (v[i + 1] - v[i]) / D;
			res += min(t, T * 2 + 1);
		}
		res += T + T + 1;
	}
	cout << res << endl;
    return 0;
}