public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  String s = sc . next ( ) ;
  Map < String , Integer > map = new HashMap < > ( ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    String t = s . substring ( i , i + 1 ) ;
    if ( map . containsKey ( t ) ) {
      map . put ( t , map . get ( t ) + 1 ) ;
    }
    else {
      map . put ( t , 1 ) ;
    }
  }
  long mod = 1000000007 ;
  long sum = 1l ;
  for ( Entry < String , Integer > entry : map . entrySet ( ) ) {
    long c = entry . getValue ( ) ;
    sum *= ( long ) ( c + 1 ) % mod ;
    sum %= ( long ) mod ;
  }
  System . out . println ( sum - 1 ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; String s = sc . next ( ) ; Map < String , Integer > map = new HashMap < > ( ) ; for ( int i = 0 ; i < n ; i ++ ) { String t = s . substring ( i , i + 1 ) ; if ( map . containsKey ( t ) ) { map . put ( t , map . get ( t ) + 1 ) ; } else { map . put ( t , 1 ) ; } } long mod = 1000000007 ; long sum = 1l ; for ( Entry < String , Integer > entry : map . entrySet ( ) ) { long c = entry . getValue ( ) ; sum *= ( long ) ( c + 1 ) % mod ; sum %= ( long ) mod ; } System . out . println ( sum - 1 ) ; }
(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: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier) (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) 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: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) consequence: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (decimal_integer_literal)))))) alternative: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (decimal_integer_literal)))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (enhanced_for_statement type: (generic_type (type_identifier) (type_arguments (type_identifier) (type_identifier))) name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (cast_expression type: (integral_type) value: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal)))) right: (identifier)))) (expression_statement (assignment_expression left: (identifier) right: (cast_expression type: (integral_type) value: (identifier)))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)))))))