using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] str = Console.ReadLine().Split(' ') ;
            int vegi = int.Parse(str[0]);
            int meat = int.Parse(str[1]);
            int bai = int.Parse(str[2]);
            int total = int.Parse(str[3]);
            int cnt = 0;
            while(true)
            {
                if(total<meat+1||meat<bai||vegi<=0||meat<=0)
                {
                    break;
                }
                vegi--;
                meat = meat - bai;
                total = total - (bai+ 1);
                cnt++;
            }
            Console.WriteLine(cnt);
        }
    }
}