#include <bits/stdc++.h>
using namespace std;
char sqr[9][9];
int check = 0;
int main() {
  for (int i = 0; i < 8; i++)
    for (int j = 0; j < 8; j++) cin >> sqr[i][j];
  for (int i = 0; i < 8; i++) {
    for (int j = 0; j < 7; j++) {
      if ((sqr[i][j] == 'W' && sqr[i][j + 1] == 'B') ||
          (sqr[i][j] == 'B' && sqr[i][j + 1] == 'W'))
        check = 0;
      else {
        check = 1;
        break;
      }
    }
    if (check == 1) break;
  }
  if (!check)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
