#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int b = 0, w = 0;
  for (int i = 0; i < 8; i++) {
    cin >> s;
    for (int j = 0; j < 8; j++) {
      if (s[j] == 'B' && s[j] != s[j + 1])
        b++;
      else if (s[j] == 'W' && s[j] != s[j + 1])
        w++;
    }
  }
  if (b == 32 && w == 32)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
