import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long A=sc.nextLong();
    long B=sc.nextLong();
    long N=sc.nextLong();
    long M=sc.nextLong();
    if(A>B){
      System.out.println(B+(A-B)/(N+1));
    }
    else{
      System.out.println(A+(B-A)/(M+1));
    }
  }
}