// Slower C++ solution:
#include<bits/stdc++.h>

#define N 111111

#define M 444444

#define LL long long

using namespace std;

int n,i,k,j,a[N];LL f[N],V1[M],V2[M],E,T;

void ins(int k,int l,int r,int x,LL z1,LL z2){

	if(l==r){V1[k]=z1;V2[k]=z2;return;}

	int md=l+r>>1;

	if(x<=md)ins(k<<1,l,md,x,z1,z2);else ins(k<<1|1,md+1,r,x,z1,z2);

	V1[k]=min(V1[k<<1],V1[k<<1|1]);

	V2[k]=min(V2[k<<1],V2[k<<1|1]);

}

LL qu1(int k,int l,int r,int x,int y){

	if(x>y)return 1e18;

	if(x<=l&&r<=y)return V1[k];

	int md=l+r>>1;

	if(y<=md)return qu1(k<<1,l,md,x,y);

	if(x>md)return qu1(k<<1|1,md+1,r,x,y);

	return min(qu1(k<<1,l,md,x,y),qu1(k<<1|1,md+1,r,x,y));

}

LL qu2(int k,int l,int r,int x,int y){

	if(x>y)return 1e18;

	if(x<=l&&r<=y)return V2[k];

	int md=l+r>>1;

	if(y<=md)return qu2(k<<1,l,md,x,y);

	if(x>md)return qu2(k<<1|1,md+1,r,x,y);

	return min(qu2(k<<1,l,md,x,y),qu2(k<<1|1,md+1,r,x,y));

}

int main(){

	for(i=0;i<M;i++)V1[i]=V2[i]=1e18;

	scanf("%d%lld%lld",&n,&E,&T);

	for(i=1;i<=n;i++)scanf("%lld",&a[i]);

	for(i=0,k=0;i<=n;i++){

		f[i]=1e18;

		for(;(a[i]-a[k+1])*2>T&&k<i;k++);

		//f[i]=f[k]+max(a[i]-a[k+1]+a[i]-a[k+1],T)+a[i]-a[k];

		//j<=k a[i]-a[j+1*2>T

		//f[i]=qu2(1,0,0,k)

	//	printf("%d %d\n",(a[i]-a[k+1])*2,T);

		if(i==0)f[i]=0;else 

		f[i]=min(qu1(1,0,n,k,i-1)+T+a[i],qu2(1,0,n,0,k-1)+1ll*a[i]*3);

		//printf("%lld %lld\n",qu1(1,0,n,k,i-1)+T+a[i],qu2(1,0,n,0,k-1)+1ll*a[i]*3);

		//printf("%d %d %lld\n",i,k,f[i]);

	//	printf("%lld %lld %d\n",qu1(1,0,n,k,i-1),qu2(1,0,n,0,k-1),T+a[i]);

		//puts("-----------------------");

			//f[i]=min(f[i],f[j]+a[i]-a[j]+max((a[i]-a[j+1])*2,T));

		

		ins(1,0,n,i,f[i]-a[i],f[i]-a[i]-a[i+1]*2);

	}

	printf("%lld\n",f[n]+E-a[n]);

}

// Faster C++ solution for the same problem (measured speedup: 8.607716938203074x):
/* --- author: dxm --- */

#include<bits/stdc++.h>

using namespace std;



#define ll long long

#define INF 2147483647

#define Inf 1e18

#define rep(i,n) for(int (i)=0;(i)<n;i++)

#define REP(i,n) for(int (i)=1;(i)<=n;i++)

#define mp make_pair

#define pb push_back

#define pii pair<int,int>

inline void Fail(){

	printf("0");

	exit(0);

}



const int maxn=100005;

int n,e,t;

ll dp[maxn];

int x[maxn],y[maxn];

class segtree{

public:

	ll tree[maxn*4];

	int leaf[maxn];

	void build(int l,int r,int node){

		if(l==r){

			leaf[l]=node;

			tree[node]=Inf;

			return;

		}

		int mid=(l+r)>>1;

		build(l,mid,node*2);

		build(mid+1,r,node*2+1); 

		tree[node]=min(tree[node*2],tree[node*2+1]);

	}

	void upd(int node,ll val){

		node=leaf[node];

		tree[node]=val;

		node>>=1;

		while(node){

			tree[node]=min(tree[node*2],tree[node*2+1]);

			node>>=1;

		}

	}

	ll query(int l,int r,int vl,int vr,int node){

		if(r<l||vr<vl)return Inf;

		if(l>vr||r<vl)return Inf;

		if(l>=vl&&r<=vr)return tree[node];

		int mid=(l+r)>>1;

		return min(query(l,mid,vl,vr,node*2),query(mid+1,r,vl,vr,node*2+1));

	}

}t1,t2;



int main(){

	scanf("%d%d%d",&n,&e,&t);

	rep(i,n)scanf("%d",&x[i]),y[i]=2*x[i];

	t1.build(0,n-1,1);

	t2.build(0,n-1,1);

	rep(i,n){

		dp[i]=max((x[i]-x[0])*2LL,1LL*t);

		int pos=lower_bound(y,y+n,2*x[i]-t)-y;

		dp[i]=min(dp[i],min(t1.query(0,n-1,0,pos-2,1)+2LL*x[i],t2.query(0,n-1,max(pos-1,0),n-1,1)+t));

		t1.upd(i,dp[i]-2LL*x[i+1]);

		t2.upd(i,dp[i]);

	}

	printf("%lld",e+dp[n-1]);

	return 0;

}



/*

Input:

-----------------

Output:

*/