public static void main ( String [ ] args ) {
  Scanner s = new Scanner ( System . in ) ;
  String a = s . next ( ) , b = s . next ( ) , c , d ;
  int loop = s . nextInt ( ) ;
  System . out . println ( a + " " + b ) ;
  for ( int i = 0 ;
  i < loop ;
  i ++ ) {
    c = s . next ( ) ;
    d = s . next ( ) ;
    if ( a . equalsIgnoreCase ( c ) ) a = d ;
    else b = d ;
    System . out . println ( a + " " + b ) ;
  }
}

public static void main ( String [ ] args ) { Scanner s = new Scanner ( System . in ) ; String a = s . next ( ) , b = s . next ( ) , c , d ; int loop = s . nextInt ( ) ; System . out . println ( a + " ▁ " + b ) ; for ( int i = 0 ; i < loop ; i ++ ) { c = s . next ( ) ; d = s . next ( ) ; if ( a . equalsIgnoreCase ( c ) ) a = d ; else b = d ; System . out . println ( a + " ▁ " + b ) ; } }
(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))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier))) (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 (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (identifier) right: (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: (identifier))) alternative: (expression_statement (assignment_expression left: (identifier) right: (identifier)))) (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)))))))))