import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc  = new Scanner (System.in);
        String s = sc.nextLine();
        boolean res = true;
        int i = 0;
        if(s.charAt(0)==s.charAt(1) && s.charAt(2)==s.charAt(0) && s.charAt(2)==s.charAt(3)){
            res = false;
        }
        else{
        if(s.charAt(i)==s.charAt(i+1)||s.charAt(i)==s.charAt(i+2)||s.charAt(i)==s.charAt(i+3)){
            if(s.charAt(i+1)==s.charAt(i+2)||s.charAt(i+1)==s.charAt(i+3)){
                
            }
            else{
                if(s.charAt(i+2)==s.charAt(i+3)){

                }
                else    
                    res = false;
            }

                
                
        }
        else{
            res = false;
        }
    }
           
        if(res == true)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz