Nth Triangular Number

Given a positive integer n, your task is to compute the n^th triangular number. The n^th triangular number is defined as the sum of the first n natural numbers. It can be calculated using the formula:

\( T_n = \frac{n(n+1)}{2} \)

For example, when n = 4, the triangular number is 10 because 1 + 2 + 3 + 4 = 10.

Ensure that your solution reads input from stdin and prints the result to stdout.

inputFormat

The input consists of a single line containing one positive integer n.

Example: 4

outputFormat

Output the n^th triangular number as a single integer.

Example: For input 4, the output should be 10.

1

1