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