#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
int main(){
	ll n,d,t;	cin>>n>>d>>t;
	vector<ll> x(n);
	for(int i=0;i<n;i++){
		cin>>x[i];
		x[i]+=1e9;
	}
	sort(x.begin(),x.end());
	map<ll,ll> use;
	ll ans=0;
	for(int i=0;i<n;i++){
		ll mod=x[i]%d;
		ll left=x[i]-d*t;	
		ll right=x[i]+d*t;
		if(use.find(mod)==use.end()){
			ans+=2*t+1;
			use.insert(make_pair(mod,right));
		}
		else if(use[mod]<left){
			ans+=2*t+1;
			use[mod]=right;
		}
		else{
			ans+=(right-use[mod])/d;
			use[mod]=right;
		}
	}
	cout<<ans<<endl;
	return 0;
}