public static void main ( String [ ] args ) {
  Scanner reader = new Scanner ( System . in ) ;
  HashSet < String > set = new HashSet < String > ( ) ;
  set . add ( reader . next ( ) ) ;
  set . add ( reader . next ( ) ) ;
  String print = "" ;
  for ( String i : set ) print += i + " " ;
  System . out . println ( print ) ;
  int t = reader . nextInt ( ) ;
  for ( int i = 0 ;
  i < t ;
  i ++ ) {
    print = "" ;
    set . remove ( reader . next ( ) ) ;
    set . add ( reader . next ( ) ) ;
    for ( String j : set ) print += j + " " ;
    System . out . println ( print ) ;
  }
}

public static void main ( String [ ] args ) { Scanner reader = new Scanner ( System . in ) ; HashSet < String > set = new HashSet < String > ( ) ; set . add ( reader . next ( ) ) ; set . add ( reader . next ( ) ) ; String print = " " ; for ( String i : set ) print += i + " ▁ " ; System . out . println ( print ) ; int t = reader . nextInt ( ) ; for ( int i = 0 ; i < t ; i ++ ) { print = " " ; set . remove ( reader . next ( ) ) ; set . add ( reader . next ( ) ) ; for ( String j : set ) print += j + " ▁ " ; System . out . println ( print ) ; } }
(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: (generic_type (type_identifier) (type_arguments (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments (type_identifier))) arguments: (argument_list)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (string_literal))) (enhanced_for_statement type: (type_identifier) name: (identifier) value: (identifier) body: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (string_literal))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (local_variable_declaration type: (integral_type) 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: (identifier) right: (string_literal))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (enhanced_for_statement type: (type_identifier) name: (identifier) value: (identifier) body: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (string_literal))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))))