#include <bits/stdc++.h>
using namespace std;
int main() {
  int max;
  int nuts;
  int sections;
  int cap;
  cin >> max;
  cin >> nuts;
  cin >> sections;
  cin >> cap;
  int box = 0;
  int divisors = 1;
  while (nuts > 0) {
    if (sections != 0) {
      while (divisors < max && sections != 0) {
        divisors++;
        sections--;
      }
    }
    nuts -= divisors * cap;
    divisors = 1;
    box++;
  }
  cout << "" << box;
  return 0;
}
