#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  vector<vector<char>> S(3,vector<char>(3));
  for(int i=0;i<3;i++)for(int j=0;j<3;j++) cin>>S[i][j];
  for(int i=0;i<3;i++){
      for(int j=0;j<2;j++){
          if(S[i][j] == S[i][j+1]){
              cout<<"No"<<endl;
              return 0;
          }
      }
  }
  for(int i=0;i<2;i++){
      for(int j=0;j<3;j++){
          if(S[i][j] == S[i+1][j]){
              cout<<"No"<<endl;
              return 0;
          }
      }
  }
  cout<<"Yes"<<endl;
}