#include <cassert>// c
#include <iostream>// io
#include <iomanip>
#include <fstream>
#include <sstream>
#include <vector>// container
#include <map>
#include <set>
#include <queue>
#include <bitset>
#include <stack>
#include <algorithm>// other
#include <complex>
#include <numeric>
#include <functional>
#include <random>
#include <regex>
using namespace std;

typedef long long ll;typedef unsigned long long ull;typedef long double ld;

#define ALL(c) c.begin(),c.end()
#define IN(l,v,r) (l<=v && v < r)
template<class T> void UNIQUE(T& v){v.erase(unique(ALL(v)),v.end());}
//debug
#define DUMP(x) cerr << #x <<" = " << (x)
#define LINE() cerr<< " (L" << __LINE__ << ")"

struct range{
	struct Iter{
		int v,step;
		Iter& operator++(){v+=step;return *this;}
		bool operator!=(Iter& itr){return v<itr.v;}
		int& operator*(){return v;}
	};
	Iter i, n;
	range(int i, int n,int step):i({i,step}), n({n,step}){}
	range(int i, int n):range(i,n,1){}
	range(int n):range(0,n){}
	Iter& begin(){return i;}
	Iter& end(){return n;}
};
struct rrange{
	struct Iter{
		int v,step;
		Iter& operator++(){v-=step;return *this;}
		bool operator!=(Iter& itr){return v>itr.v;}
		int& operator*(){return v;}
	};
	Iter i, n;
	rrange(int i, int n,int step):i({i-1,step}), n({n-1,step}){}
	rrange(int i, int n):rrange(i,n,1){}
	rrange(int n) :rrange(0,n){}
	Iter& begin(){return n;}
	Iter& end(){return i;}
};

//input
template<typename T1,typename T2> istream& operator >> (istream& is,pair<T1,T2>& p){return is>>p.first>>p.second;}
template<typename T1> istream& operator >> (istream& is,tuple<T1>& t){return is >> get<0>(t);}
template<typename T1,typename T2> istream& operator >> (istream& is,tuple<T1,T2>& t){return is >> get<0>(t) >> get<1>(t);}
template<typename T1,typename T2,typename T3> istream& operator >> (istream& is,tuple<T1,T2,T3>& t){return is >>get<0>(t)>>get<1>(t)>>get<2>(t);}
template<typename T1,typename T2,typename T3,typename T4> istream& operator >> (istream& is,tuple<T1,T2,T3,T4>& t){return is >> get<0>(t)>>get<1>(t)>>get<2>(t)>>get<3>(t);}
template<typename T> istream& operator >> (istream& is,vector<T>& as){for(int i:range(as.size()))is >>as[i];return is;}
//output
template<typename T> ostream& operator << (ostream& os, const set<T>& ss){for(auto a:ss){if(a!=ss.begin())os<<" "; os<<a;}return os;}
template<typename T1,typename T2> ostream& operator << (ostream& os, const pair<T1,T2>& p){return os<<p.first<<" "<<p.second;}
template<typename K,typename V> ostream& operator << (ostream& os, const map<K,V>& m){bool isF=true;for(auto& p:m){if(!isF)os<<endl;os<<p;isF=false;}return os;}
template<typename T1> ostream& operator << (ostream& os, const tuple<T1>& t){return os << get<0>(t);}
template<typename T1,typename T2> ostream& operator << (ostream& os, const tuple<T1,T2>& t){return os << get<0>(t)<<" "<<get<1>(t);}
template<typename T1,typename T2,typename T3> ostream& operator << (ostream& os, const tuple<T1,T2,T3>& t){return os << get<0>(t)<<" "<<get<1>(t)<<" "<<get<2>(t);}
template<typename T1,typename T2,typename T3,typename T4> ostream& operator << (ostream& os, const tuple<T1,T2,T3,T4>& t){return os << get<0>(t)<<" "<<get<1>(t)<<" "<<get<2>(t)<<" "<<get<3>(t);}
template<typename T> ostream& operator << (ostream& os, const vector<T>& as){for(int i:range(as.size())){if(i!=0)os<<" "; os<<as[i];}return os;}
template<typename T> ostream& operator << (ostream& os, const vector<vector<T>>& as){for(int i:range(as.size())){if(i!=0)os<<endl; os<<as[i];}return os;}

// values
template<typename T> inline T INF(){assert(false);};
template<> inline int INF<int>(){return 1<<28;};
template<> inline ll INF<ll>(){return 1LL<<58;};
template<> inline double INF<double>(){return 1e16;};
template<> inline long double INF<long double>(){return 1e16;};

template<class T> inline T EPS(){assert(false);};
template<> inline int EPS<int>(){return 1;};
template<> inline ll EPS<ll>(){return 1LL;};
template<> inline double EPS<double>(){return 1e-8;};
template<> inline long double EPS<long double>(){return 1e-8;};

// min{2^r | n < 2^r}
template<typename T> T upper_pow2(T n){ T res=1;while(res<n)res<<=1;return res;}
// max{d | 2^d  <= n}
template<typename T> T msb(T n){ int d=62;while((1LL<<d)>n)d--;return d;}

template<typename T,typename U> T pmod(T v,U M){return (v%M+M)%M;}


template<class T> class SegmentTree{
public:
	const int size,n2;vector<T> dat;

	T e(){ return INF<T>();}
	T c(T a,T b){return min(a,b);}

	// T me(){return 0;}
	// T mc(T a,T b){return a + b;}
	SegmentTree(int n):size(n),n2(upper_pow2(size)){
		dat=vector<T>(n2*2,e());
	}
	inline T get(int v){return dat[v+n2];}
	void set(int v,T a){
		v+=n2;dat[v]=a;
		while(v!=1){
			int parent=v/=2,chl=parent*2,chr=parent*2+1;
			dat[parent]=c(dat[chl],dat[chr]);
		}
	}
	T query(int a,int b){return query(a,b,1,0,n2);} //[a,b)
private:
	T query(int a,int b,int v,int l,int r){ //[a,b) on v:[l,r)
		if(r<=a || b<=l)return e();//out of range
		if(a<=l && r<=b)return dat[v];
		T lv=query(a,b,v*2,l,(l+r)/2),rv=query(a,b,v*2+1,(l+r)/2,r);
		return c(lv,rv);
	}
};

template <typename T,typename Func>
T satisfy_mini(Func P,T l ,T r){//(l |sep| r)
	l--;
	while(r-l>EPS<T>()){
		T m=(l+r)/2;
		(P(m)?r:l)=m;
	}
	return r;
}


class Main{
	public:

	void run(){
		int N;ll E,T;cin >> N >> E >> T;
		vector<ll> xs(N+1);
		for(int i:range(N)) cin >> xs[i+1];


		vector<ll> dp(N+1,INF<ll>());

		SegmentTree<ll> seg1(N+1);
		// seg1[i] = dp[i] - xs[i] - 2 * xs[i+1];
		SegmentTree<ll> seg2(N+1);
		// seg2[i] = dp[i] - xs[i];
		dp[0] = 0;
		seg1.set(0,dp[0]-xs[0]-2*xs[1]);
		seg2.set(0,dp[0]-xs[0]);
		// seg.set(0,0);
		for(int i:range(1,N+1)){
			// ll d = xs[i] - xs[pre+1];
			// dp[i] = min(dp[i],xs[i] +  dp[pre] - xs[pre] + max(2*d,T));
			// dp[i] = min(3*xs[i] + min{pre < t}(seg1[pre]), xs[i] + T + min{pre >= t}(seg2[pre]))
			int t = satisfy_mini([&](int pre){
				return 2*(xs[i]-xs[pre+1]) <= T;
			},-1,i);
			// cerr << t <<" " <<  2*(xs[i]-xs[t+1])  <<" " << T << endl;
			// cerr << t <<":" << i << endl;
			// cerr << 3*xs[i] + seg1.query(0,t) << "::" << xs[i] + T + seg2.query(t,i) << endl;
			dp[i] = min(3*xs[i] + seg1.query(0,t),xs[i] + T + seg2.query(t,i));
			seg1.set(i,dp[i] - xs[i] - 2 * xs[i+1]);
			seg2.set(i,dp[i] - xs[i]);
		}
		cout << dp[N] + E - xs[N] << endl;
	}
};

int main(){
	cout <<fixed<<setprecision(20);
	cin.tie(0);
	ios::sync_with_stdio(false);
	Main().run();
	return 0;
}


Measured memory_bytes: 5888