#include <stdio.h>
#include <stdbool.h>

void main(void){
    char pattern[3][4] = {"a","a","a"};
    for(int i = 0 ; i < 3 ; i++){
        scanf("%s",pattern[i]);
    }
    bool flg = true;
    for(int i = 0 ; i < 3 ; i++){
        for(int j = 0 ; j < 3 ; j++){
            if(i != 2 && pattern[i][j] == pattern[i+1][j] || j != 2 && pattern[i][j] == pattern[i][j+1]){
                flg = false;
                break;
            }
        }
        if(!flg){
            break;
        }
    }
    if(flg){
        printf("Yes");
    }else{
        printf("No");
    }
}