using System;
using static System.Console;
using static System.Math;

public class Hello{
    public static void Main(){
        string[] input = ReadLine().Split(' ');
        int[] x = new int[input.Length];
        for(int i=0;i<input.Length;i++){
            x[i] = int.Parse(input[i]);
        }
        
        int m2 = 1;
        for(int i=0;i<x[1];i++){
            m2 *= 2;
        }
        
        int month = 0;
        while(x[0] > 0){
            month++;
            int tsuki = month % 12;
            if(tsuki == 0){
                tsuki = 12;
            }
            if(x[2] <= tsuki && tsuki <= x[2] + x[3] - 1){
                x[0] -= m2;
            }else{
                x[0] -= x[1];
            }
        }
        WriteLine(month);
    }
}