#include <bits/stdc++.h>
using namespace std;
template <typename T>
void prn(T first) {
  cout << first << "\n";
}
template <typename T, typename... Args>
void prn(T first, Args... args) {
  cout << first << " ";
  prn(args...);
}
int main() {
  long long i, j, n, k;
  string s;
  bool flag = true;
  for (i = 0; i < 8; i++) {
    cin >> s;
    for (j = 1; j < 8; j++) {
      flag = flag and ((s[j - 1] == 'W' and s[j] == 'B') or
                       (s[j - 1] == 'B' and s[j] == 'W'));
    }
  }
  if (flag)
    printf("YES\n");
  else
    printf("NO\n");
  return 0;
}
