import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
 
public class Main {
    public static void main(String args[]) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Arrays; Arrays java.util public class Main {
    public static void main(String args[]) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    }
} Main public static void main(String args[]) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    } main {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String S = br.readLine(); S br.readLine() br.readLine br char array[] = S.toCharArray(); array S.toCharArray() S.toCharArray S Arrays.sort(array) Arrays.sort Arrays array if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No"); array[0] == array[1] && array[1] != array[2] && array[2] == array[3] array[0] == array[1] && array[1] != array[2] && array[2] == array[3] array[0] == array[1] array[0] array 0 array[1] array 1 array[1] != array[2] array[1] array 1 array[2] array 2 array[2] == array[3] array[2] array 2 array[3] array 3 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[]) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    }
} public class Main {
    public static void main(String args[]) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
 
public class Main {
    public static void main(String args[]) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String S = br.readLine();
	char array[] = S.toCharArray();
	Arrays.sort(array);
	if (array[0] == array[1] && array[1] != array[2] && array[2] == array[3])
	    System.out.println("Yes");
	else
	    System.out.println("No");
    }
}