import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			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) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	} main {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			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[] c = S.toCharArray(); c S.toCharArray() S.toCharArray S if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		} c[0] == c[1] && c[2] == c[3] && c[1] != c[2] c[0] == c[1] && c[2] == c[3] && c[1] != c[2] c[0] == c[1] c[0] c 0 c[1] c 1 c[2] == c[3] c[2] c 2 c[3] c 3 c[1] != c[2] c[1] c 1 c[2] c 2 {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		} c[0] == c[2] && c[1] == c[3] && c[2] != c[3] c[0] == c[2] && c[1] == c[3] && c[2] != c[3] c[0] == c[2] c[0] c 0 c[2] c 2 c[1] == c[3] c[1] c 1 c[3] c 3 c[2] != c[3] c[2] c 2 c[3] c 3 {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		} c[0] == c[3] && c[1] == c[2] && c[2] != c[3] c[0] == c[3] && c[1] == c[2] && c[2] != c[3] c[0] == c[3] c[0] c 0 c[3] c 3 c[1] == c[2] c[1] c 1 c[2] c 2 c[2] != c[3] c[2] c 2 c[3] c 3 {
			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) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		//入力表示
		String S = sc.next();

		char[] c = S.toCharArray();

		if (c[0] == c[1] && c[2] == c[3] && c[1] != c[2]) {
			System.out.println("Yes");
		} else if (c[0] == c[2] && c[1] == c[3] && c[2] != c[3]) {
			System.out.println("Yes");
		} else if (c[0] == c[3] && c[1] == c[2] && c[2] != c[3]) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
}