#include <bits/stdc++.h>
using namespace std;
int a, b, k, v;
int main() {
  scanf("%d %d %d %d", &k, &a, &b, &v);
  int tmp = 0;
  if (b >= k - 1) {
    int tmp = b / (k - 1);
    int tmp1 = b % (k - 1);
    int yao = a / (k * v);
    if (yao < tmp) {
      if (a - yao * (k * v) == 0) {
        printf("%d\n", yao);
        return 0;
      } else {
        printf("%d\n", yao + 1);
        return 0;
      }
    } else {
      int yu = a - tmp * k * v;
      int ans = 0;
      if (yu <= (tmp1 + 1) * v) {
        printf("%d\n", tmp + 1);
      } else {
        yu -= (tmp1 + 1) * v;
        int temp = yu / v;
        if (yu % v != 0) temp++;
        printf("%d\n", temp + tmp + 1);
      }
    }
  } else {
    tmp = b + 1;
    int ans = 0;
    if ((b + 1) * v >= a) {
      printf("1\n");
      return 0;
    } else {
      ans = 1;
      a -= (b + 1) * v;
      int tmp1 = a / v;
      if (a % v != 0) tmp1++;
      ans += tmp1;
      printf("%d\n", ans);
    }
  }
}
