public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  String line = sc . nextLine ( ) ;
  if ( line . equals ( "A" ) ) {
    System . out . println ( "T" ) ;
  }
  else if ( line . equals ( "T" ) ) {
    System . out . println ( "A" ) ;
  }
  else if ( line . equals ( "C" ) ) {
    System . out . println ( "G" ) ;
  }
  else if ( line . equals ( "G" ) ) {
    System . out . println ( "C" ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; String line = sc . nextLine ( ) ; if ( line . equals ( " A " ) ) { System . out . println ( " T " ) ; } else if ( line . equals ( " T " ) ) { System . out . println ( " A " ) ; } else if ( line . equals ( " C " ) ) { System . out . println ( " G " ) ; } else if ( line . equals ( " G " ) ) { System . out . println ( " C " ) ; } }
(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)))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))))))))))