#include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>
#include <vector>
#include <set>

#define rep(x,to) for(int (x)=(0);(x)<(to);(x)++)

using namespace std;
typedef long long ll;


int main()
{
	
	ll N, D, T, res=0;
	cin >> N >> D >> T;
	vector<ll> X(N);
	rep(i,N) cin >> X[i];
	
	vector<int> am(N);
	rep(i,N) am[i]=X[i]%D;
	set<ll> st;
	rep(i,N) st.insert(am[i]);
	ll r = st.size();
	res = r * (2 * T + 1);
	
	for(auto x: st){
		ll mx=-1, mn=1LL<<55;
		rep(i,N) if(x==am[i]){
			mx = max(mx, X[i]);
			mn = min(mn, X[i]);
		}
		res +=(mx-mn)/D;
	
	}
	
	cout << res << endl;
	return 0;
}