import java.io.*;
import java.util.*;

public class Main{
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		char[] alphabet = {'A' , 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M' , 'N', 'O', 'P', 'Q' , 'R', 'S', 'T', 'U', 'V', 'W', 'X','Y','Z'};
		String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
		int[] freqArr = new int[alphabet.length];
		String S = sc.nextLine();
		for (int i = 0; i < 4; i++) {
			freqArr[alpha.indexOf(S.charAt(i))]++;
		}
		int cnt = 0;
		for(int i : freqArr){
			if(i >= 2){
				cnt++;
			}
			if(cnt >= 2){
				System.out.println("Yes");
				System.exit(0);
			}
		}
		System.out.println("No");
	}


static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}

		public String next() throws IOException
		{
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {return Integer.parseInt(next());}

		public long nextLong() throws IOException {return Long.parseLong(next());}

		public String nextLine() throws IOException {return br.readLine();}

		public boolean ready() throws IOException {return br.ready();}

		public double nextDouble(String x)
		{

			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			boolean dec = false, neg = false;
			int start = 0;
			if(x.charAt(0) == '-')
			{
				neg = true;
				start++;
			}
			for(int i = start; i < x.length(); i++)
				if(x.charAt(i) == '.')
				{
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				}
				else
				{
					sb.append(x.charAt(i));
					if(dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg?-1:1);
		}


	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz