static int printPermutation ( int n ) {
  if ( n % 2 != 0 ) {
    System . out . println ( "-1" ) ;
  }
  else for ( int i = 1 ;
  i <= n / 2 ;
  i ++ ) {
    System . out . print ( 2 * i + " " + ( ( 2 * i ) - 1 ) + " " ) ;
  }
  return n ;
}

static int printPermutation ( int n ) { if ( n % 2 != 0 ) { System . out . println ( " - 1" ) ; } else for ( int i = 1 ; i <= n / 2 ; i ++ ) { System . out . print ( 2 * i + " ▁ " + ( ( 2 * i ) - 1 ) + " ▁ " ) ; } return n ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (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 (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (binary_expression left: (binary_expression left: (decimal_integer_literal) right: (identifier)) right: (string_literal)) right: (parenthesized_expression (binary_expression left: (parenthesized_expression (binary_expression left: (decimal_integer_literal) right: (identifier))) right: (decimal_integer_literal)))) right: (string_literal)))))))) (return_statement (identifier))))