#include <bits/stdc++.h>
char num[10][10];
int main() {
  for (int i = 1; i < 9; i++) scanf("%s", num[i]);
  bool yes = true;
  for (int i = 1; i <= 8; i++) {
    int cntb = 0, cntw = 0;
    char pre = '*';
    for (int j = 0; j < 8; j++) {
      if (num[i][j] == pre) {
        yes = false;
        break;
      }
      if (num[i][j] == 'W') {
        cntw++;
        pre = num[i][j];
      }
      if (num[i][j] == 'B') {
        cntb++;
        pre = num[i][j];
      }
    }
    if (cntb != cntw) {
      yes = false;
    }
  }
  printf("%s\n", yes ? "YES" : "NO");
  return 0;
}
