import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	static class FastReader{
		BufferedReader br;
		StringTokenizer st;
		public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		}
		String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		}
		int nextInt() {
			return Integer.parseInt(next());
		}
	}
	public static void main(String[] args) {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	}

} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
	static class FastReader{
		BufferedReader br;
		StringTokenizer st;
		public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		}
		String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		}
		int nextInt() {
			return Integer.parseInt(next());
		}
	}
	public static void main(String[] args) {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	}

} Main public static void main(String[] args) {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	} main {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	} FastReader ob = new FastReader(); ob new FastReader() String s = ob.next(); s ob.next() ob.next ob int arr[] = new int[2]; arr new int[2] 2 for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		} int i=0; int i=0; i 0 i<s.length() i s.length() s.length s i++ i++ i {
			arr[s.charAt(i)-'A']++;
		} {
			arr[s.charAt(i)-'A']++;
		} arr[s.charAt(i)-'A']++ arr[s.charAt(i)-'A'] arr s.charAt(i)-'A' s.charAt(i) s.charAt s i 'A' if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		} arr[0]==3 || arr[1]==3 arr[0]==3 arr[0] arr 0 3 arr[1]==3 arr[1] arr 1 3 {
			System.out.println("No");
			return;
		} System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args static class FastReader{
		BufferedReader br;
		StringTokenizer st;
		public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		}
		String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		}
		int nextInt() {
			return Integer.parseInt(next());
		}
	} FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		} FastReader {
			br =  new BufferedReader(new InputStreamReader(System.in));
		} br =  new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		} next {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		} while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			} st==null || !st.hasMoreElements() st==null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			} try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				} catch(IOException e) {
					e.printStackTrace();
				} IOException e {
					e.printStackTrace();
				} e.printStackTrace() e.printStackTrace e {
					st = new StringTokenizer(br.readLine());
					
				} st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public class Main {
	static class FastReader{
		BufferedReader br;
		StringTokenizer st;
		public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		}
		String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		}
		int nextInt() {
			return Integer.parseInt(next());
		}
	}
	public static void main(String[] args) {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	}

} public class Main {
	static class FastReader{
		BufferedReader br;
		StringTokenizer st;
		public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		}
		String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		}
		int nextInt() {
			return Integer.parseInt(next());
		}
	}
	public static void main(String[] args) {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	}

} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	static class FastReader{
		BufferedReader br;
		StringTokenizer st;
		public FastReader() {
			br =  new BufferedReader(new InputStreamReader(System.in));
		}
		String next() {
			while(st==null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
					
				}
				catch(IOException e) {
					e.printStackTrace();
				}
				
			}
			return st.nextToken();
		}
		int nextInt() {
			return Integer.parseInt(next());
		}
	}
	public static void main(String[] args) {
		FastReader ob = new FastReader();
		String s = ob.next();
		int arr[] = new int[2];
		for(int i=0;i<s.length();i++) {
			arr[s.charAt(i)-'A']++;
		}
		if(arr[0]==3 || arr[1]==3) {
			System.out.println("No");
			return;
		}
		System.out.println("Yes");
		
	}

}
