#include<cstdio>
#include<iostream>
using namespace std;
 
int p[100001],s[100001],l,r;
long long f[100001];
int main(){
	int n,e,t;scanf("%d%d%d",&n,&e,&t);
	for(int i=1;i<=n;i++)scanf("%d",&p[i]);
	long long z=2e9;
	for(int i=1;i<=n;i++){
		s[++r]=i;
		for(;2*(p[i]-p[s[l]])>=t;l++)
			z=min(z,f[s[l]-1]-2*p[s[l]]);
		f[i]=f[s[l]-1]+t;
		f[i]=min(f[i],2*p[i]+z);
	}
	cout<<f[n]+e;
}