Program to calculate series 10+9+8+...+n" in java with output

import java.util.Scanner;

class Main {

 public static int calcSeries(int n) {

   int sum = 0;

   for(int i=10; i>=n; i--) {

     sum += i;

   }

   return sum;

 }

 public static void main(String[] args) {

   Scanner reader = new Scanner(System.in);

   int n = 0;

   do {

     System.out.print("Enter n: ");

     n = reader.nextInt();

     if (n >= 10) {

       System.out.println("Please enter a value lower than 10.");

     }

   } while (n >= 10);

   reader.close();

   System.out.printf("sum: %d\n", calcSeries(n));

 }

}