#include <bits/stdc++.h>
using namespace std;
int main() {
  bool f, ans = 1;
  char mat[8][8];
  for (int i = 0; i < 8; i++)
    for (int j = 0; j < 8; j++) {
      cin >> mat[i][j];
      if (j) {
        if (f) {
          if (mat[i][j] == 'B')
            f = 0;
          else
            ans = 0;
        } else {
          if (mat[i][j] == 'W')
            f = 1;
          else
            ans = 0;
        }
      } else {
        if (mat[i][j] == 'W')
          f = 1;
        else
          f = 0;
      }
    }
  if (ans)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
