public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  int p ;
  p = input . nextInt ( ) ;
  int ans = 0 ;
  for ( int x = 1 ;
  x < p ;
  x ++ ) {
    boolean flag = true ;
    int tmp = 1 ;
    for ( int i = 1 ;
    i < p - 1 ;
    i ++ ) {
      tmp *= x ;
      if ( ( tmp - 1 ) % p == 0 ) {
        flag = false ;
        break ;
      }
      tmp %= p ;
    }
    if ( flag ) {
      if ( ( tmp * x - 1 ) % p == 0 ) {
        ans ++ ;
      }
    }
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; int p ; p = input . nextInt ( ) ; int ans = 0 ; for ( int x = 1 ; x < p ; x ++ ) { boolean flag = true ; int tmp = 1 ; for ( int i = 1 ; i < p - 1 ; i ++ ) { tmp *= x ; if ( ( tmp - 1 ) % p == 0 ) { flag = false ; break ; } tmp %= p ; } if ( flag ) { if ( ( tmp * x - 1 ) % p == 0 ) { ans ++ ; } } } 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))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (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 (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier) value: (true))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (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: (binary_expression left: (identifier) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (identifier)) right: (decimal_integer_literal))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (false))) (break_statement))) (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (if_statement condition: (parenthesized_expression (identifier)) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) right: (identifier)) right: (decimal_integer_literal))) consequence: (block (expression_statement (update_expression (identifier))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))