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