public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  long n = input . nextLong ( ) ;
  long a = ( long ) Math . pow ( 10 , ( long ) Math . log10 ( n ) ) - 1 ;
  long b = n - a ;
  int sum = 0 ;
  while ( a > 0 ) {
    sum += a % 10 ;
    a /= 10 ;
  }
  while ( b > 0 ) {
    sum += b % 10 ;
    b /= 10 ;
  }
  System . out . println ( sum ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; long n = input . nextLong ( ) ; long a = ( long ) Math . pow ( 10 , ( long ) Math . log10 ( n ) ) - 1 ; long b = n - a ; int sum = 0 ; while ( a > 0 ) { sum += a % 10 ; a /= 10 ; } while ( b > 0 ) { sum += b % 10 ; b /= 10 ; } System . out . println ( sum ) ; }
(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: (integral_type) 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: (binary_expression left: (cast_expression type: (integral_type) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal) (cast_expression type: (integral_type) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))) right: (decimal_integer_literal)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (while_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) body: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))) (expression_statement (assignment_expression left: (identifier) right: (decimal_integer_literal))))) (while_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) body: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))) (expression_statement (assignment_expression left: (identifier) right: (decimal_integer_literal))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))