//ｺｯwwｺｯwwｺｹｯwwwｺｯwwｺｹｯwwwｺｹｯｺｯwwwｺｯwwｺｯwwｺｹｯwwwｺｯwwｺｹｯwwwｺｹｯｺｯwwwｺｹｰｰｰｰｯ!!!wwwwwｺｯwwｺｯwwｺｹｯwwwｺｯwwｺｹｯwwwｺｹｯｺｯwwwｺｯwwｺｯwwｺｹｯwwwｺｯwwwｺｹｯwwwｺｹｯｺｯwwwｺｹｰｰｰｰｯ!!!wwwwwｺｹｯｺｯｯｺｰｰｰｰ!!!!!!wwwwwwwwwww
import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[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();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[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();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[2]){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[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 char[] a = new char[4]; a new char[4] 4 for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        } int i = 0 ; int i = 0 ; i 0 i < 4 i 4 i++ i++ i {
            a[i] = s.charAt(i);
        } {
            a[i] = s.charAt(i);
        } a[i] = s.charAt(i) a[i] a i s.charAt(i) s.charAt s i sc.close() sc.close sc Arrays.sort(a) Arrays.sort Arrays a if(a[0] == a[1] && a[1] != a[2] && a[3] == a[2]){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        } a[0] == a[1] && a[1] != a[2] && a[3] == a[2] a[0] == a[1] && a[1] != a[2] && a[3] == a[2] 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[3] == a[2] a[3] a 3 a[2] a 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();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[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();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[2]){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} Main
//ｺｯwwｺｯwwｺｹｯwwwｺｯwwｺｹｯwwwｺｹｯｺｯwwwｺｯwwｺｯwwｺｹｯwwwｺｯwwｺｹｯwwwｺｹｯｺｯwwwｺｹｰｰｰｰｯ!!!wwwwwｺｯwwｺｯwwｺｹｯwwwｺｯwwｺｹｯwwwｺｹｯｺｯwwwｺｯwwｺｯwwｺｹｯwwwｺｯwwwｺｹｯwwwｺｹｯｺｯwwwｺｹｰｰｰｰｯ!!!wwwwwｺｹｯｺｯｯｺｰｰｰｰ!!!!!!wwwwwwwwwww
import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        char[] a = new char[4];
        for(int i = 0 ; i < 4 ; i++){
            a[i] = s.charAt(i);
        }
        sc.close();
        Arrays.sort(a);
        if(a[0] == a[1] && a[1] != a[2] && a[3] == a[2]){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
}