#include <bits/stdc++.h>
using namespace std;
int a, b, v, k, n, box;
int main() {
  cin >> k >> a >> b >> v;
  n = a / v;
  if (a % v) n++;
  if (n <= b + 1) {
    box = n / k;
    if (n % k) box++;
  } else {
    box = b / (k - 1);
    b = b % (k - 1);
    n -= box * k;
    if (b) {
      box++;
      n -= (b + 1);
    }
    box += n;
  }
  cout << box << endl;
  return 0;
}
