import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    }
} Main public static void main(String[] args) {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    } main {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String S =sc.next(); S sc.next() sc.next sc char[] a = S.toCharArray(); a S.toCharArray() S.toCharArray S if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        } a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3] a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3] a[0]==a[1] a[0] a 0 a[1] a 1 a[1]!=a[2] a[1] a 1 a[2] a 2 a[2]==a[3] a[2] a 2 a[3] a 3 {
          System.out.print("Yes");
        } System.out.print("Yes") System.out.print System.out System System.out "Yes" if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        } a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1] a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1] a[0]==a[2] a[0] a 0 a[2] a 2 a[2]!=a[3] a[2] a 2 a[3] a 3 a[3]==a[1] a[3] a 3 a[1] a 1 {
        System.out.print("Yes");
        } System.out.print("Yes") System.out.print System.out System System.out "Yes" if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        } a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2] a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2] a[0]==a[3] a[0] a 0 a[3] a 3 a[3]!=a[1] a[3] a 3 a[1] a 1 a[1]==a[2] a[1] a 1 a[2] a 2 {
         System.out.print("Yes");
        } System.out.print("Yes") System.out.print System.out System System.out "Yes" {
        System.out.print("No");
        } System.out.print("No") System.out.print System.out System System.out "No" String[] args args public class Main {
    public static void main(String[] args) {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    }
} public class Main {
    public static void main(String[] args) {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    }
} Main
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
    
    Scanner sc = new Scanner(System.in);
 
      String S =sc.next();
      char[] a = S.toCharArray();
      
        if(a[0]==a[1]&& a[1]!=a[2]&& a[2]==a[3]){
          System.out.print("Yes");
        }
        else if(a[0]==a[2]&& a[2]!=a[3]&& a[3]==a[1]){
        System.out.print("Yes");
        }
        else if(a[0]==a[3]&& a[3]!=a[1]&& a[1]==a[2]){
         System.out.print("Yes");
        }else{
        System.out.print("No");
        }
    }
}