#include <bits/stdc++.h>
using namespace std;
int main() {
  int t = 8, w = 0, b = 0;
  bool test = true;
  vector<string> V(8);
  for (int i = 0; i < t; ++i) {
    getline(cin, V[i]);
  }
  for (int i = 0; i < t; ++i) {
    for (int j = 0; j < t; ++j) {
      if (V[i].substr(j, 1) == "W")
        w++;
      else if (V[i].substr(j, 1) == "B")
        b++;
    }
    if (V[i].find("WW") != string::npos || V[i].find("BB") != string::npos) {
      test = false;
      break;
    }
  }
  if (b == 32 && w == 32 && test == true)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
