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