class Program
{
    static void Main(string[] args)
    {
        string[] input = Console.ReadLine()!.Split(' ');
        int vegetable = int.Parse(input[0]);
        int meat = int.Parse(input[1]);
        int multiple = int.Parse(input[2]);
        int max = int.Parse(input[3]);

        for (int i = 1; i < max; i++)
        {
            if (i * multiple > meat)
            {
                Console.WriteLine(i - 1);
                return;
            }
        }
    }
}