#include <bits/stdc++.h>
bool checkAlterante(int *b) {
  int sum, start;
  sum = start = b[0];
  for (int i = 1; i < 8; i++) {
    sum += b[i];
    if (sum != 0 && sum != start) return false;
  }
  return true;
}
int main() {
  int board[8][8];
  char ch;
  for (int i = 0; i < 8; i++) {
    for (int j = 0; j < 8; j++) {
      scanf("%c", &ch);
      board[i][j] = (ch == 'W' ? 1 : -1);
    }
    scanf("%*c");
  }
  for (int i = 0; i < 8; i++) {
    if (!checkAlterante(board[i])) {
      printf("NO\n");
      return 0;
    }
  }
  printf("YES\n");
  return 0;
}
