public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int N = sc . nextInt ( ) ;
  String S = sc . next ( ) ;
  long mod = 1000000007 ;
  long [ ] cnt = new long [ 26 ] ;
  for ( int i = 0 ;
  i < N ;
  i ++ ) {
    cnt [ S . charAt ( i ) - 'a' ] ++ ;
  }
  long ans = 1 ;
  for ( long i : cnt ) {
    ans = ( i + 1 ) * ans % mod ;
  }
  ans -= 1 ;
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int N = sc . nextInt ( ) ; String S = sc . next ( ) ; long mod = 1000000007 ; long [ ] cnt = new long [ 26 ] ; for ( int i = 0 ; i < N ; i ++ ) { cnt [ S . charAt ( i ) - ' a ' ] ++ ; } long ans = 1 ; for ( long i : cnt ) { ans = ( i + 1 ) * ans % mod ; } ans -= 1 ; System . out . println ( ans ) ; }
(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: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (decimal_integer_literal))))) (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 (expression_statement (update_expression (array_access array: (identifier) index: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (enhanced_for_statement type: (integral_type) name: (identifier) value: (identifier) body: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (identifier)) right: (identifier)))))) (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))))))