public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  String name = sc . next ( ) ;
  String names [ ] = name . split ( "" ) ;
  String ans = "" ;
  if ( name . length ( ) % 2 == 0 ) {
    String a = name . substring ( 0 , name . length ( ) / 2 ) ;
    String b = name . substring ( ( name . length ( ) / 2 ) , name . length ( ) ) ;
    String [ ] aa = a . split ( "" ) ;
    String [ ] bb = b . split ( "" ) ;
    for ( int i = 0 ;
    i < a . length ( ) ;
    i ++ ) {
      if ( ! aa [ i ] . equals ( bb [ b . length ( ) - ( i + 1 ) ] ) ) {
        ans = "NO" ;
      }
      else {
        ans = "YES" ;
      }
    }
  }
  else {
    int j = name . length ( ) - 1 ;
    int l = ( j / 2 ) ;
    String c = name . substring ( 0 , l ) ;
    String d = name . substring ( l + 1 , name . length ( ) ) ;
    String [ ] cc = c . split ( "" ) ;
    String [ ] dd = d . split ( "" ) ;
    for ( int k = 0 ;
    k < l ;
    k ++ ) {
      if ( ! cc [ k ] . equals ( dd [ d . length ( ) - ( k + 1 ) ] ) ) {
        ans = "NO" ;
      }
      else {
        ans = "YES" ;
      }
    }
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; String name = sc . next ( ) ; String names [ ] = name . split ( " " ) ; String ans = " " ; if ( name . length ( ) % 2 == 0 ) { String a = name . substring ( 0 , name . length ( ) / 2 ) ; String b = name . substring ( ( name . length ( ) / 2 ) , name . length ( ) ) ; String [ ] aa = a . split ( " " ) ; String [ ] bb = b . split ( " " ) ; for ( int i = 0 ; i < a . length ( ) ; i ++ ) { if ( ! aa [ i ] . equals ( bb [ b . length ( ) - ( i + 1 ) ] ) ) { ans = " NO " ; } else { ans = " YES " ; } } } else { int j = name . length ( ) - 1 ; int l = ( j / 2 ) ; String c = name . substring ( 0 , l ) ; String d = name . substring ( l + 1 , name . length ( ) ) ; String [ ] cc = c . split ( " " ) ; String [ ] dd = d . split ( " " ) ; for ( int k = 0 ; k < l ; k ++ ) { if ( ! cc [ k ] . equals ( dd [ d . length ( ) - ( k + 1 ) ] ) ) { ans = " NO " ; } else { ans = " YES " ; } } } 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: (type_identifier) 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) dimensions: (dimensions) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (string_literal))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal))) (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (unary_expression operand: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))))))))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (string_literal)))) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (string_literal)))))))) alternative: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal) (identifier))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)) (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_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 (if_statement condition: (parenthesized_expression (unary_expression operand: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))))))))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (string_literal)))) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (string_literal))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))