import java.util.*;
import java.io.*;
import java.lang.*;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        String a = sc.next();

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

        String a = sc.next();

        if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        String a = sc.next();

        if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    } main {
        Scanner sc = new Scanner(System.in);

        String a = sc.next();

        if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String a = sc.next(); a sc.next() sc.next sc if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No"); a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)) a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)) a.charAt(0) == a.charAt(1) a.charAt(0) a.charAt a 0 a.charAt(1) a.charAt a 1 (a.charAt(2) == a.charAt(3)) a.charAt(2) a.charAt a 2 a.charAt(3) a.charAt a 3 (a.charAt(0) != a.charAt(2)) a.charAt(0) a.charAt a 0 a.charAt(2) a.charAt a 2 System.out.println("Yes") System.out.println System.out System System.out "Yes" if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No"); a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)) a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)) a.charAt(0) == a.charAt(2) a.charAt(0) a.charAt a 0 a.charAt(2) a.charAt a 2 (a.charAt(1) == a.charAt(3)) a.charAt(1) a.charAt a 1 a.charAt(3) a.charAt a 3 (a.charAt(0) != a.charAt(1)) a.charAt(0) a.charAt a 0 a.charAt(1) a.charAt a 1 System.out.println("Yes") System.out.println System.out System System.out "Yes" if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No"); a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)) a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)) a.charAt(0) == a.charAt(3) a.charAt(0) a.charAt a 0 a.charAt(3) a.charAt a 3 (a.charAt(1) == a.charAt(2)) a.charAt(1) a.charAt a 1 a.charAt(2) a.charAt a 2 (a.charAt(0) != a.charAt(1)) a.charAt(0) a.charAt a 0 a.charAt(1) a.charAt a 1 System.out.println("Yes") System.out.println System.out System System.out "Yes" 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 a = sc.next();

        if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(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 a = sc.next();

        if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} Main
import java.util.*;
import java.io.*;
import java.lang.*;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        String a = sc.next();

        if (a.charAt(0) == a.charAt(1) && (a.charAt(2) == a.charAt(3)) && (a.charAt(0) != a.charAt(2)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(2) && (a.charAt(1) == a.charAt(3)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else if (a.charAt(0) == a.charAt(3) && (a.charAt(1) == a.charAt(2)) && (a.charAt(0) != a.charAt(1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    }
}
