public static void main ( String [ ] args ) throws Exception {
  Scanner sc = new Scanner ( System . in ) ;
  String s = sc . next ( ) ;
  sc . close ( ) ;
  String [ ] str = s . split ( "" ) ;
  Arrays . sort ( str , Comparator . reverseOrder ( ) ) ;
  long ans = 0 ;
  for ( int i = 0 ;
  i < s . length ( ) ;
  i ++ ) {
    if ( str [ i ] . equals ( "B" ) ) {
      ans += i ;
    }
  }
  for ( int i = 0 ;
  i < s . length ( ) ;
  i ++ ) {
    if ( s . charAt ( i ) == 'B' ) {
      ans -= i ;
    }
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) throws Exception { Scanner sc = new Scanner ( System . in ) ; String s = sc . next ( ) ; sc . close ( ) ; String [ ] str = s . split ( " " ) ; Arrays . sort ( str , Comparator . reverseOrder ( ) ) ; long ans = 0 ; for ( int i = 0 ; i < s . length ( ) ; i ++ ) { if ( str [ i ] . equals ( " B " ) ) { ans += i ; } } for ( int i = 0 ; i < s . length ( ) ; i ++ ) { if ( s . charAt ( i ) == ' B ' ) { ans -= i ; } } System . out . println ( ans ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_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) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))