#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 9;

ll N, D, T;
ll X[100];
const ll offset = 1e10;

ll calc(vector<ll> v) {
	sort(v.begin(), v.end());

	ll res = T * 2;
	rep (i, v.size() - 1) {
		res += min(v[i + 1] - v[i] - 1, 2 * T);
	}
	res += v.size();
	return res;
}

int main() {
	cin >> N >> D >> T;
	rep (i, N) {
		cin >> X[i];
		X[i] += offset;
	}

	map<ll, vector<ll>> m;

	rep (i, N) {
		m[X[i] % D].push_back(X[i] / D);
	}

	ll ans = 0;
	for (auto p : m) {
		ans += calc(p.second);
	}
	cout << ans << endl;

	return 0;
}