import java.util.*;
public class Main{
  public static void main(String args[]){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  }
} import java.util.*; util.* java public class Main{
  public static void main(String args[]){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  }
} Main public static void main(String args[]){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  } main {
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  } Scanner sc=new Scanner(System.in); sc new Scanner(System.in) String str=sc.next(); str sc.next() sc.next sc char[] c=str.toCharArray(); c str.toCharArray() str.toCharArray str if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    } c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1] c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1] c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] c[0]==c[1] c[0] c 0 c[1] c 1 c[2]==c[3] c[2] c 2 c[3] c 3 c[0]!=c[2] c[0] c 0 c[2] c 2 c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1] c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1] c[0]==c[2] c[0] c 0 c[2] c 2 c[1]==c[3] c[1] c 1 c[3] c 3 c[0]!=c[1] c[0] c 0 c[1] c 1 c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1] c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1] c[0]==c[3] c[0] c 0 c[3] c 3 c[1]==c[2] c[1] c 1 c[2] c 2 c[0]!=c[1] c[0] c 0 c[1] c 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 public class Main{
  public static void main(String args[]){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  }
} public class Main{
  public static void main(String args[]){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  }
} Main
import java.util.*;
public class Main{
  public static void main(String args[]){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    char[] c=str.toCharArray();



    if(c[0]==c[1] && c[2]==c[3] &&c[0]!=c[2] || c[0]==c[2] && c[1]==c[3]&&c[0]!=c[1]||c[0]==c[3] && c[1]==c[2]&&c[0]!=c[1]){
      System.out.println("Yes");
    }else{

        System.out.println("No");
    }
  
  }
}