public static void main ( String [ ] args ) throws IOException {
  Scanner sc = new Scanner ( System . in ) ;
  int r = sc . nextInt ( ) ;
  int c = sc . nextInt ( ) ;
  char [ ] [ ] mat = new char [ r ] [ c ] ;
  for ( int i = 0 ;
  i < r ;
  i ++ ) {
    String s = sc . next ( ) ;
    for ( int j = 0 ;
    j < c ;
    j ++ ) {
      mat [ i ] [ j ] = s . charAt ( j ) ;
    }
  }
  for ( int i = 0 ;
  i < r ;
  i ++ ) {
    for ( int j = 0 ;
    j < c ;
    j ++ ) {
      if ( i % 2 == 0 && mat [ i ] [ j ] == '.' ) {
        if ( j % 2 == 0 ) {
          mat [ i ] [ j ] = 'B' ;
        }
        else {
          mat [ i ] [ j ] = 'W' ;
        }
      }
      else if ( i % 2 != 0 && mat [ i ] [ j ] == '.' ) {
        if ( j % 2 == 0 ) {
          mat [ i ] [ j ] = 'W' ;
        }
        else {
          mat [ i ] [ j ] = 'B' ;
        }
      }
    }
  }
  for ( int i = 0 ;
  i < r ;
  i ++ ) {
    for ( int j = 0 ;
    j < c ;
    j ++ ) {
      System . out . print ( mat [ i ] [ j ] ) ;
    }
    System . out . println ( ) ;
  }
}

public static void main ( String [ ] args ) throws IOException { Scanner sc = new Scanner ( System . in ) ; int r = sc . nextInt ( ) ; int c = sc . nextInt ( ) ; char [ ] [ ] mat = new char [ r ] [ c ] ; for ( int i = 0 ; i < r ; i ++ ) { String s = sc . next ( ) ; for ( int j = 0 ; j < c ; j ++ ) { mat [ i ] [ j ] = s . charAt ( j ) ; } } for ( int i = 0 ; i < r ; i ++ ) { for ( int j = 0 ; j < c ; j ++ ) { if ( i % 2 == 0 && mat [ i ] [ j ] == ' . ' ) { if ( j % 2 == 0 ) { mat [ i ] [ j ] = ' B ' ; } else { mat [ i ] [ j ] = ' W ' ; } } else if ( i % 2 != 0 && mat [ i ] [ j ] == ' . ' ) { if ( j % 2 == 0 ) { mat [ i ] [ j ] = ' W ' ; } else { mat [ i ] [ j ] = ' B ' ; } } } } for ( int i = 0 ; i < r ; i ++ ) { for ( int j = 0 ; j < c ; j ++ ) { System . out . print ( mat [ i ] [ j ] ) ; } System . out . println ( ) ; } }
(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: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier)) dimensions: (dimensions_expr (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: (identifier)) 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)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (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: (identifier)) 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: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (character_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (block (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (character_literal)))) alternative: (block (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (character_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (character_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (block (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (character_literal)))) alternative: (block (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (character_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: (identifier)) 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: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list)))))))