import java.util.Scanner;

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

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