import java.util.*; 
 
class Main{
public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
       
		String s=sc.next();
       
		String[] s1=s.split("");
    	
 	if(s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2]))){
    		System.out.println("Yes");
    	}else if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    }
    }
} import java.util.*; util.* java class Main{
public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
       
		String s=sc.next();
       
		String[] s1=s.split("");
    	
 	if(s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2]))){
    		System.out.println("Yes");
    	}else if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    }
    }
} Main public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
       
		String s=sc.next();
       
		String[] s1=s.split("");
    	
 	if(s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2]))){
    		System.out.println("Yes");
    	}else if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    }
    } main {
	Scanner sc=new Scanner(System.in);
       
		String s=sc.next();
       
		String[] s1=s.split("");
    	
 	if(s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2]))){
    		System.out.println("Yes");
    	}else if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    }
    } Scanner sc=new Scanner(System.in); sc new Scanner(System.in) String s=sc.next(); s sc.next() sc.next sc String[] s1=s.split(""); s1 s.split("") s.split s "" if(s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2]))){
    		System.out.println("Yes");
    	}else if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    } s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2])) s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2])) s1[0].equals(s1[1]) s1[0].equals s1[0] s1 0 s1[1] s1 1 s1[2].equals(s1[3]) s1[2].equals s1[2] s1 2 s1[3] s1 3 !(s1[0].equals(s1[2])) (s1[0].equals(s1[2])) s1[0].equals s1[0] s1 0 s1[2] s1 2 {
    		System.out.println("Yes");
    	} System.out.println("Yes") System.out.println System.out System System.out "Yes" if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    } s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2])) s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2])) s1[0].equals(s1[3]) s1[0].equals s1[0] s1 0 s1[3] s1 3 s1[2].equals(s1[1]) s1[2].equals s1[2] s1 2 s1[1] s1 1 !(s1[0].equals(s1[2])) (s1[0].equals(s1[2])) s1[0].equals s1[0] s1 0 s1[2] s1 2 {
     		System.out.println("Yes");
   	 } System.out.println("Yes") System.out.println System.out System System.out "Yes" if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    } s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1])) s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1])) s1[0].equals(s1[2]) s1[0].equals s1[0] s1 0 s1[2] s1 2 s1[1].equals(s1[3]) s1[1].equals s1[1] s1 1 s1[3] s1 3 !(s1[0].equals(s1[1])) (s1[0].equals(s1[1])) s1[0].equals s1[0] s1 0 s1[1] s1 1 {
    System.out.println("Yes");
    } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
 
    	System.out.println("No");
    } System.out.println("No") System.out.println System.out System System.out "No" String[] args args
import java.util.*; 
 
class Main{
public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
       
		String s=sc.next();
       
		String[] s1=s.split("");
    	
 	if(s1[0].equals(s1[1])&&s1[2].equals(s1[3])&&!(s1[0].equals(s1[2]))){
    		System.out.println("Yes");
    	}else if(s1[0].equals(s1[3])&&s1[2].equals(s1[1])&&!(s1[0].equals(s1[2]))){
     		System.out.println("Yes");
   	 }else if(s1[0].equals(s1[2])&&s1[1].equals(s1[3])&&!(s1[0].equals(s1[1]))){
    System.out.println("Yes");
    }else{
 
    	System.out.println("No");
    }
    }
}