#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, p, q;
  cin >> n >> p >> q;
  vector<int> c(n);
  for (int i = 0; i < n; ++i) scanf("%d", &c[i]);
  long long x = 0;
  for (int i = 0; i < n; ++i) {
    if (c[i] > p * (2 * n - 2 * i - 2 + q)) {
      x += c[i];
      q--;
    } else {
      x += p * q;
      q++;
    }
  }
  cout << x << endl;
  return 0;
}
