public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  String arr [ ] [ ] = new String [ 8 ] [ 8 ] ;
  for ( int i = 0 ;
  i < 8 ;
  i ++ ) {
    String str = sc . nextLine ( ) ;
    arr [ i ] = str . split ( "" ) ;
  }
  boolean b = true ;
  for ( int i = 0 ;
  i < 8 ;
  i ++ ) {
    for ( int j = 1 ;
    j < 8 ;
    j ++ ) {
      if ( arr [ i ] [ j - 1 ] . equals ( arr [ i ] [ j ] ) ) {
        b = false ;
        break ;
      }
    }
  }
  System . out . println ( ( b ) ? "YES" : "NO" ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; String arr [ ] [ ] = new String [ 8 ] [ 8 ] ; for ( int i = 0 ; i < 8 ; i ++ ) { String str = sc . nextLine ( ) ; arr [ i ] = str . split ( " " ) ; } boolean b = true ; for ( int i = 0 ; i < 8 ; i ++ ) { for ( int j = 1 ; j < 8 ; j ++ ) { if ( arr [ i ] [ j - 1 ] . equals ( arr [ i ] [ j ] ) ) { b = false ; break ; } } } System . out . println ( ( b ) ? " YES " : " NO " ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) dimensions: (dimensions) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (decimal_integer_literal)) dimensions: (dimensions_expr (decimal_integer_literal))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier) value: (true))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (method_invocation object: (array_access array: (array_access array: (identifier) index: (identifier)) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) name: (identifier) arguments: (argument_list (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier))))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (false))) (break_statement))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (ternary_expression condition: (parenthesized_expression (identifier)) consequence: (string_literal) alternative: (string_literal)))))))