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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        char[][] values = new char[3][];
        for (int i = 0; i < 3; i++) {
            values[i] = sc.next().toCharArray();
            for (int j = 0; j < 3; j++) {
                if ((i > 0 && values[i][j] == values[i - 1][j]) || (j > 0 && values[i][j] == values[i][j - 1])){
                    System.out.println("No");
                    return;
                }
            }
        }
        System.out.println("Yes");
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}