import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		String S=scan.next();
		char[] y=S.toCharArray();
		if(y[0]==y[1] && y[1]!=y[2] && y[2]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[2] && y[2]!=y[1] && y[1]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[3] && y[3]!=y[1] && y[1]==y[2]) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		String S=scan.next();
		char[] y=S.toCharArray();
		if(y[0]==y[1] && y[1]!=y[2] && y[2]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[2] && y[2]!=y[1] && y[1]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[3] && y[3]!=y[1] && y[1]==y[2]) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	}

} Main public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		String S=scan.next();
		char[] y=S.toCharArray();
		if(y[0]==y[1] && y[1]!=y[2] && y[2]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[2] && y[2]!=y[1] && y[1]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[3] && y[3]!=y[1] && y[1]==y[2]) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	} main {
		Scanner scan=new Scanner(System.in);
		String S=scan.next();
		char[] y=S.toCharArray();
		if(y[0]==y[1] && y[1]!=y[2] && y[2]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[2] && y[2]!=y[1] && y[1]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[3] && y[3]!=y[1] && y[1]==y[2]) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

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

	}

} public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		String S=scan.next();
		char[] y=S.toCharArray();
		if(y[0]==y[1] && y[1]!=y[2] && y[2]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[2] && y[2]!=y[1] && y[1]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[3] && y[3]!=y[1] && y[1]==y[2]) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		String S=scan.next();
		char[] y=S.toCharArray();
		if(y[0]==y[1] && y[1]!=y[2] && y[2]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[2] && y[2]!=y[1] && y[1]==y[3])
		{
			System.out.println("Yes");
		}
		else if(y[0]==y[3] && y[3]!=y[1] && y[1]==y[2]) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	}

}