#include <algorithm>
#include <iostream>
#include <iterator>
#include <string>
#include <vector>

int main() {
  std::vector<std::string> s(3);
  std::copy_n(std::istream_iterator<std::string>(std::cin), 3, s.begin());

  for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < 3; ++j) {
      if (i + 1 < 3 && s[i][j] == s[i + 1][j]) {
        std::cout << "No\n";
        return 0;
      }
      if (j + 1 < 3 && s[i][j] == s[i][j + 1]) {
        std::cout << "No\n";
        return 0;
      }
    }
  }

  std::cout << "Yes\n";
}