#include "bits/stdc++.h"
using namespace std;

typedef long long Int;
#define REP(i,n) for(int (i)=0;(i)<(int)(n);++(i))

Int solve(vector<Int> v, Int D, Int T) {
	vector<pair<Int, int>> rs;
	for (auto x : v) {
		x /= D;
		rs.emplace_back(make_pair(x - T, +1));
		rs.emplace_back(make_pair(x + T, -1));
	}

	auto comp = [](pair<Int, int> a, pair<Int, int> b) { return a.first != b.first ? a.first < b.first : a.second > b.second;  };
	sort(rs.begin(), rs.end(), comp);

	Int res = 0;
	int open_count = 0;
	Int open_pos = -1;
	for (auto r : rs) {
		open_count += r.second;
		if (open_count == 0) {
			Int close_pos = r.first;
			res += close_pos - open_pos + 1;
		}
		if (open_count == 1 && r.second == 1) {
			open_pos = r.first;
		}
	}
	return res;
}

int main() {
	int N, D, T;
	cin >> N >> D >> T;
	Int x[100];
	REP(i, N) {
		cin >> x[i]; x[i] += 1000000000;
	}
	map<int, vector<Int> > mp;
	REP(i, N){
		mp[x[i] % D].push_back(x[i]);
	}
	Int ans = 0;
	for (auto it = mp.begin(); it != mp.end(); ++it) {
		ans += solve(it->second, D, T);
	}
	cout << ans << endl;
}