#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;}
vector<PP> cht;
ll id=0;
void add(ll a,ll b,ll num){
    // out(a);out(b);out(num);
    while(cht.size()){
        if(get<0>(cht.back())==a){
            if(b>=get<2>(cht.back()))return;
            cht.pop_back();
        }
        else break;
    }
    while(cht.size()>1){
        auto p=cht[cht.size()-2],q=cht.back();
        if((a-get<0>(q))*(b-get<1>(p))>(get<1>(q)-b)*(get<0>(p)-a))break;
        cht.pop_back();
    }
    cht.eb(a,b,num);
}
P getmi(ll x){
    while(id<cht.size()-1){
        if(get<0>(cht[id])*x+get<1>(cht[id])<get<0>(cht[id+1])*x+get<1>(cht[id+1]))break;
        id++;
    }
    return P(get<0>(cht[id])*x+get<1>(cht[id]),get<2>(cht[id]));
}
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;
    REP(i,1,n+1){
        add(-2*(i-1)*b,dp[i-1]+b*((i-1)*(i-1)+(i-1))+2*a*(i-1),0);
        dp[i]=getmi(i).fi+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);
}