ll m, b;

long double intersectX(Func other) {

return (long double)(b-other.b)/(other.m-m);

}

cin.tie(0)->sync_with_stdio(0);

cin >> n >> a >> b >> c;

F0R(i, n) cin >> A[i];

ps[0] = A[0];

FOR(i, 1, n) ps[i] = ps[i-1] + A[i];

deque<Func> functions;

functions.pb(Func{b, 0});

vector<int> ints(n); F0R(i, n) ints[i] = i;

for (int i = 0; i < n; i++) {

int idx = *lower_bound(ints.begin(), ints.begin()+functions.size()-1, ps[i], [&functions](int idx, ll x) {

return functions[idx].intersectX(functions[idx+1]) < x;

});

ll val = functions[idx].m*ps[i]+functions[idx].b + a*ps[i]*ps[i] + c;

if (i == n-1) cout << val << endl;

else {

Func f = {-2LL*a*ps[i]+b, val+a*ps[i]*ps[i]-b*ps[i]};

while (functions.size() >= 2 && f.intersectX(functions[functions.size()-1]) <= functions[functions.size()-1].intersectX(functions[functions.size()-2])) {

functions.pop_back();

}

functions.push_back(f);

}

}

return 0;