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