#include <iostream>
#include <string>
#include <vector>
int main(void) {
  
  std::vector<std::string> v;
  
  for (int i = 0; i < 3; i++) {
    std::string s;
    std::cin >> s;
    v.push_back(s);
  }
  
  bool f = true;
  
  for (int i = 0; i < v.size(); i++) {
    for (int j = 0; j < v[i].size(); j++) {
      if (i > 0) if (v[i][j] == v[i-1][j]) f = false;
      if (j < v[i].size()-1) if (v[i][j] == v[i][j+1]) f = false;
      if (i < v.size()-1) if (v[i][j] == v[i+1][j]) f = false;
      if (j > 0) if (v[i][j] == v[i][j-1]) f = false;
      if (!f) break;
    }
  }
  
  std::cout << (f ? "Yes" : "No") << std::endl;
  return 0;
}