#include <bits/stdc++.h>
using namespace std;
int cnt[4444];
vector<int> v;
int main() {
  int k, a, b, c = 0, v;
  int i, j, l, need_sec, need_box, s = 0;
  cin >> k >> a >> b >> v;
  need_sec = a / v;
  if (a % v != 0) need_sec++;
  for (i = 1; s < need_sec; i++) {
    if (b >= k - 1) {
      b -= (k - 1);
      s += k;
      c++;
    } else {
      s += (b + 1);
      b = 0;
      c++;
    }
  }
  cout << c << '\n';
  return 0;
}
