Exercise 4.25

import java.util.Scanner;

public class Exercise4_25 {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    System.out.print("Enter a number: ");
    int number = in.nextInt();
    int sum = 0;
    for (int i = 1; i <= number; i++) {
      for (var j = 1; j <= i; j++) {
        sum += j;
      }
    }
    System.out.println("The sum upto " + number + " is " + sum);
  }
}