#include <bits/stdc++.h>
using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef pair<LL, LL> PLL;

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

#define FF first
#define SS second
template<class S, class T>
istream& operator>>(istream& is, pair<S,T>& p){
  return is >> p.FF >> p.SS;
}

const double EPS = 1e-10;
const double PI  = acos(-1.0);
const LL MOD = 1e9+7;

const int MAX = 300010;
LL N, A, B, W;
int ls[MAX], rs[MAX];
LL f(LL x){
  return -x*A + x*(x+1)/2 * B;
}
int main(){
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  cin >> N >> A >> B >> W;
  vector<PLL> xs(N);
  REP(i,N){
	cin >> xs[i].FF;
	xs[i].SS = i;
	xs[i].FF += A;
	ls[i] = rs[i] = -1;
  }
  sort(RALL(xs));

  REP(i,N){
	int l, r, ix = xs[i].SS;
	if(ix > 0){
	  if(ls[ix-1] < 0) l = ix;
	  else l = ls[ix-1];
	}
	else l = 0;

	if(ix+1 < N){
	  if(rs[ix+1] < 0) r = ix;
	  else r = rs[ix+1];
	}
	else r = N-1;

	int n = r - l + 1;
	if(n*B <= xs[i].FF){
	  xs[i].FF = n*B;
	  ls[ix] = l;
	  rs[ix] = r;
	}
  }

  LL ans = 0;
  REP(i,N) ans += xs[i].FF;
  cout << W+ans - N * A << endl;

  return 0;
}