using System;
public class Hello{
    public static void Main(){
        
        var inpt = Console.ReadLine().Split();
        
        int v = int.Parse(inpt[0]), m = int.Parse(inpt[1]), n = int.Parse(inpt[2]), f = int.Parse(inpt[3]);
        
        int ate=0;
        
        while(true){
            if(m<n || f<n+1 ||v==0)break;
            m-=n;
            v-=1;
            f-=n+1;
            ate++;
        }
        
        Console.WriteLine(ate);
    }
}