private static BigInteger P ( long n , long r ) {
  BigInteger res = BigInteger . ONE ;
  for ( long i = n ;
  i > n - r ;
  -- i ) {
    res = res . multiply ( BigInteger . valueOf ( i ) ) ;
  }
  return res ;
}

private static BigInteger P ( long n , long r ) { BigInteger res = BigInteger . ONE ; for ( long i = n ; i > n - r ; -- i ) { res = res . multiply ( BigInteger . valueOf ( i ) ) ; } return res ; }
(method_declaration (modifiers) type: (type_identifier) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (field_access object: (identifier) field: (identifier)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (identifier))) condition: (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))))) (return_statement (identifier))))