import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

class LiChaoTree:
    def __init__(self, xx, getmin=1):
        self._inf = (1 << 63)-1
        self._rev = getmin*2-1
        self._n = 1 << (len(xx)-1).bit_length()
        self._aa = [None]*(2*self._n)
        self._bb = [None]*(2*self._n)
        self._ll = [None]*(2*self._n)
        self._rr = [None]*(2*self._n)
        self._xtou = {}
        for u, x in enumerate(xx, self._n):
            self._ll[u] = self._rr[u] = x
            self._xtou[x] = u
        for u in range(1, self._n)[::-1]:
            self._ll[u], self._rr[u] = self._ll[u*2], self._rr[u*2+1]
            if self._rr[u] == None: self._rr[u] = self._rr[u*2]

    def add_line(self, a, b):
        u = 1
        while 1:
            if self._ll[u] == None: return
            if self._aa[u] == None:
                self._aa[u], self._bb[u] = a, b
                return
            c, d = self._aa[u], self._bb[u]
            l, r = self._ll[u], self._rr[u]
            yl, yr = a*l+b, a*r+b
            zl, zr = c*l+d, c*r+d
            if (yl-zl)*self._rev >= 0 and (yr-zr)*self._rev >= 0: return
            if (yl-zl)*self._rev <= 0 and (yr-zr)*self._rev <= 0:
                self._aa[u], self._bb[u] = a, b
                return
            if ((a-c)*self._rr[u*2]+b-d)*self._rev <= 0: a, b, self._aa[u], self._bb[u], yr, zr = c, d, a, b, zr, yr
            u = u*2+((yr-zr)*self._rev < 0)

    def __getitem__(self, x):
        if self._aa[1] == None: return self._rev*self._inf
        u = self._xtou[x]
        res = self._aa[1]*x+self._bb[1]
        while u > 1:
            if self._aa[u] != None:
                cur = self._aa[u]*x+self._bb[u]
                if (cur-res)*self._rev < 0: res = cur
            u >>= 1
        return res

n, a, b, w = LI()
dd = LI()

cht = LiChaoTree(list(range(n)))
cht.add_line(0, 2*w)

ans = w+n*(n+1)//2*b-a*n
for i, d in enumerate(dd):
    cur = (cht[i]+i*(b*(i+1)-2*a)+2*d)//2
    r = n-i-1
    ans = min(ans, cur+r*(r+1)//2*b-a*r)
    i += 1
    cht.add_line(-2*b*i, 2*cur+i*(b*(i-1)+2*a))

print(ans)