#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, p, q;
  cin >> n >> p >> q;
  long long A = 0;
  vector<long long> in(n);
  for (long long(i) = (0); (i) < (n); ++i) cin >> in[i];
  for (long long(i) = (0); (i) < (n); ++i) A += p * (q + i);
  int count = 0;
  for (int i = n - 1; i >= 0; i--) {
    if (in[i] - (n + q - 1) * p > 0) {
      A += in[i] - (n + q - 1) * p;
    } else
      ;
  }
  cout << A << endl;
}
