public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  String a = input . next ( ) ;
  String b = input . next ( ) ;
  int n = input . nextInt ( ) ;
  System . out . println ( a + " " + b ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    String c = input . next ( ) ;
    if ( a . equals ( c ) ) a = input . next ( ) ;
    else b = input . next ( ) ;
    System . out . println ( a + " " + b ) ;
  }
  input . close ( ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; String a = input . next ( ) ; String b = input . next ( ) ; int n = input . nextInt ( ) ; System . out . println ( a + " ▁ " + b ) ; for ( int i = 0 ; i < n ; i ++ ) { String c = input . next ( ) ; if ( a . equals ( c ) ) a = input . next ( ) ; else b = input . next ( ) ; System . out . println ( a + " ▁ " + b ) ; } input . close ( ) ; }
(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) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (type_identifier) 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)))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (string_literal)) 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: (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)))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) alternative: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (string_literal)) right: (identifier))))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))