public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  String s = sc . next ( ) ;
  for ( int i = 0 ;
  i < s . length ( ) ;
  i ++ ) {
    for ( int j = 0 ;
    j < s . length ( ) ;
    j ++ ) {
      if ( s . charAt ( i ) == s . charAt ( j ) && i != j ) {
        System . out . println ( "no" ) ;
        return ;
      }
    }
  }
  System . out . println ( "yes" ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; String s = sc . next ( ) ; for ( int i = 0 ; i < s . length ( ) ; i ++ ) { for ( int j = 0 ; j < s . length ( ) ; j ++ ) { if ( s . charAt ( i ) == s . charAt ( j ) && i != j ) { System . out . println ( " no " ) ; return ; } } } System . out . println ( " yes " ) ; }
(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)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))