#include <bits/stdc++.h>
using namespace std;
#define rep(i, n)  for(long long i=0;i<(long long)(n);i++)
#define REP(i,k,n) for(long long i=k;i<(long long)(n);i++)
#define all(a) a.begin(),a.end()
#define pb emplace_back
#define eb emplace_back
#define lb(v,k) (lower_bound(all(v),k)-v.begin())
#define ub(v,k) (upper_bound(all(v),k)-v.begin())
#define fi first
#define se second
#define pi M_PI
#define PQ(T) priority_queue<T>
#define SPQ(T) priority_queue<T,vector<T>,greater<T>>
#define dame(a) {out(a);return 0;}
#define decimal cout<<fixed<<setprecision(15);
#define dupli(a) {sort(all(a));a.erase(unique(all(a)),a.end());}
typedef long long ll;
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> PP;
typedef tuple<ll,ll,ll,ll> PPP;
typedef multiset<ll> S;
using vi=vector<ll>;
using vvi=vector<vi>;
using vvvi=vector<vvi>;
using vvvvi=vector<vvvi>;
using vp=vector<P>;
using vvp=vector<vp>;
using vb=vector<bool>;
using vvb=vector<vb>;
const ll inf=1001001001001001001;
const ll INF=1001001001;
const ll mod=1000000007;
const double eps=1e-10;
template<class T> bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<class T> bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T> void out(T a){cout<<a<<'\n';}
template<class T> void outp(T a){cout<<'('<<a.fi<<','<<a.se<<')'<<'\n';}
template<class T> void outvp(T v){rep(i,v.size())cout<<'('<<v[i].fi<<','<<v[i].se<<')';cout<<'\n';}
template<class T> void outvvp(T v){rep(i,v.size())outvp(v[i]);}
template<class T> void outv(T v){rep(i,v.size()){if(i)cout<<' ';cout<<v[i];}cout<<'\n';}
template<class T> void outvv(T v){rep(i,v.size())outv(v[i]);}
template<class T> bool isin(T x,T l,T r){return (l)<=(x)&&(x)<=(r);}
template<class T> void yesno(T b){if(b)out("yes");else out("no");}
template<class T> void YesNo(T b){if(b)out("Yes");else out("No");}
template<class T> void YESNO(T b){if(b)out("YES");else out("NO");}
template<class T> void noyes(T b){if(b)out("no");else out("yes");}
template<class T> void NoYes(T b){if(b)out("No");else out("Yes");}
template<class T> void NOYES(T b){if(b)out("NO");else out("YES");}
void outs(ll a,ll b){if(a>=inf-100)out(b);else out(a);}
ll gcd(ll a,ll b){if(b==0)return a;return gcd(b,a%b);}
ll modpow(ll a,ll b){ll res=1;a%=mod;while(b){if(b&1)res=res*a%mod;a=a*a%mod;b>>=1;}return res;}
vi query;
vp seg; // P(傾き、切片）
ll N;
void init(){
    N=1;
    while(N<query.size())N*=2;
    seg=vp(N*2-1,P(0,inf));
    while(query.size()!=N)query.pb(query.back());
}
ll getmi(ll i){
    ll x=query[i],res=inf;
    i=N+i-1;
    if(seg[i].se!=inf)chmin(res,seg[i].fi*x+seg[i].se);
    while(i>0){
        i=(i-1)/2;
        if(seg[i].se!=inf)chmin(res,seg[i].fi*x+seg[i].se);
    }
    return res;
}
void add(ll k,ll l,ll r,P p){
    ll m=(l+r)/2,R=query[r-1],L=query[l],M=query[m];
    if(L*seg[k].fi+seg[k].se>L*p.fi+p.se||seg[k].se==inf)swap(seg[k],p);
    if(R*seg[k].fi+seg[k].se<=R*p.fi+p.se||p.se==inf)return;
    if(M*seg[k].fi+seg[k].se<M*p.fi+p.se)add(k*2+2,m,r,p);
    else{
        swap(seg[k],p);
        add(k*2+1,l,m,p);
    }
}
int main(){
    ll n,a,b,w;cin>>n>>a>>b>>w;
    vi v(n);rep(i,n)cin>>v[i];
    vi dp(n+1,inf);
    dp[0]=w*2;
    query=vi(n);
    rep(i,n)query[i]=i+1;
    init();
    REP(i,1,n+1){
        add(0,0,N,P(-2*(i-1)*b,dp[i-1]+b*((i-1)*(i-1)+(i-1))+2*a*(i-1)));
        dp[i]=getmi(i-1)+2*v[i-1]+b*(i*i-i)-2*a*(i-1);
    }
    ll ans=inf;
    rep(i,n+1)chmin(ans,dp[i]/2+(n-i)*(n-i+1)/2*b-a*(n-i));
    out(ans);
}