#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  int k, a, b, v, s, boxes = 0;
  cin >> k >> a >> b >> v;
  s = a / v + (bool)(a % v);
  while (s > 0) {
    boxes++;
    if (b > 0) {
      s -= min(k, b + 1);
      b -= min(k - 1, b);
    } else
      s--;
  }
  cout << boxes;
}
