import java.util.*;
public class Test12 {
  public static void main(String[] args){
    Scanner sc=new Scanner(System.in);
    String[] line;
    String regex=" ",result="";
    line=sc.nextLine().split(regex);
    int vege=Integer.parseInt(line[0]);
    int meat=Integer.parseInt(line[1]);
    int require=Integer.parseInt(line[2]);
    int capa=Integer.parseInt(line[3]);
    int eaten=0;
    while(true){
      meat-=require;
      vege-=1;
      capa-=require+1;
      if(meat<0||vege<0||capa<0) break;
      eaten++;
    }
    result+=eaten;
    System.out.println(result);
    sc.close();
  }
}