import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    String s=sc.next();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        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 s=sc.next();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        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();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        System.out.println("Yes");
    }else{
        System.out.println("No");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    String s=sc.next();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        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 int count=0; count 0 for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    } int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    } {
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    } for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      } int j=i+1; int j=i+1; j i+1 i 1 j<4 j 4 j++ j++ j {
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      } {
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      } if(s.charAt(i)==s.charAt(j)){
          count++;
        } s.charAt(i)==s.charAt(j) s.charAt(i) s.charAt s i s.charAt(j) s.charAt s j {
          count++;
        } count++ count if(count==2){
        System.out.println("Yes");
    }else{
        System.out.println("No");
    } count==2 count 2 {
        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 s=sc.next();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        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 s=sc.next();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        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 s=sc.next();
    int count=0;
    for(int i=0;i<3;i++){
      for(int j=i+1;j<4;j++){
        if(s.charAt(i)==s.charAt(j)){
          count++;
        }
      }
    }
    if(count==2){
        System.out.println("Yes");
    }else{
        System.out.println("No");
    }
  }
}
