//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  vector<vector<char>> X(5, vector<char>(5, '-'));

  for(int i = 1; i <= 3; i++){
    for(int j = 1; j <= 3; j++){
      cin >> X[i][j];
    }
  }

  vector<int> my = {-1, 0, 0, 1};
  vector<int> mx = {0, -1, 1, 0};

  for(int i = 1; i <= 3; i++){
    for(int j = 1; j <= 3; j++){
      for(int k = 0; k < 4; k++){
        int MY = i+my[k];
        int MX = j+mx[k];

        if(X[i][j] == X[MY][MX]){
          printl("No");

          return 0;
        }
      }
    }
  }

  printl("Yes");
  return 0;
}