public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  String s = sc . next ( ) ;
  char [ ] a = new char [ n ] , b = new char [ n ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    a [ i ] = s . charAt ( i ) ;
    b [ i ] = s . charAt ( 2 * n - 1 - i ) ;
  }
  HashMap < String , Long > am = get ( a ) , bm = get ( b ) ;
  Set < String > keyset = am . keySet ( ) ;
  long res = 0 ;
  for ( String str : keyset ) {
    try {
      long aa = am . get ( str ) , bb = bm . get ( str ) ;
      res += aa * bb ;
    }
    catch ( Exception e ) {
    }
  }
  System . out . println ( res ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; String s = sc . next ( ) ; char [ ] a = new char [ n ] , b = new char [ n ] ; for ( int i = 0 ; i < n ; i ++ ) { a [ i ] = s . charAt ( i ) ; b [ i ] = s . charAt ( 2 * n - 1 - i ) ; } HashMap < String , Long > am = get ( a ) , bm = get ( b ) ; Set < String > keyset = am . keySet ( ) ; long res = 0 ; for ( String str : keyset ) { try { long aa = am . get ( str ) , bb = bm . get ( str ) ; res += aa * bb ; } catch ( Exception e ) { } } System . out . println ( res ) ; }
(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: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier)))) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier))))) (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 (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (binary_expression left: (decimal_integer_literal) right: (identifier)) right: (decimal_integer_literal)) right: (identifier)))))))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier) (type_identifier))) declarator: (variable_declarator name: (identifier) value: (method_invocation name: (identifier) arguments: (argument_list (identifier)))) declarator: (variable_declarator name: (identifier) value: (method_invocation name: (identifier) arguments: (argument_list (identifier))))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (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))) (enhanced_for_statement type: (type_identifier) name: (identifier) value: (identifier) body: (block (try_statement body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))))) (catch_clause (catch_formal_parameter (catch_type (type_identifier)) name: (identifier)) body: (block))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))