/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
  public static void main(String[] args) {
		try(Scanner s = new Scanner(System.in))
		{
			int n = s.nextInt();
			int d = s.nextInt();
			int k = s.nextInt();
			int j = s.nextInt();
 
			//여기부터 작성해 주세요
			System.out.println(winner(n,d,k,j));
		}
  }
 
	public static int winner(int n, int d, int k, int j) {
		ArrayList<Integer> people = new ArrayList();
		int pos = k;
 
		for(int i=1;i<=n;i++)
			people.add(i);
 
		people.remove(pos);
		while(people.size() != 1) {
			pos = (pos + j) % people.size();
			people.remove(pos);
		}
		return people.get(0);
	}
}
 

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