#include <bits/stdc++.h>
using namespace std;
const long base = 1000000000;
const long maxn = 200005;
const long logn = 20;
const long inf = 1e9;
const long mod = 1000000007;
const long alpha = 26;
const double pi = 3.1415926535;
int main() {
  ios_base::sync_with_stdio(0);
  setlocale(LC_ALL, "");
  int k, a, b, v;
  cin >> k >> a >> b >> v;
  int n = (a + v - 1) / v, ans = 0;
  while (n > 0) {
    if (b < k)
      n -= (b + 1), b = 0;
    else
      n -= k, b -= k - 1;
    ans++;
  }
  printf("%d", ans);
}
