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Time and Space ComplexityCoding problems

Time and Space Complexity: coding problems

Write a program that reads the input and prints the answer. Run checks it against every test, including hidden ones.

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Your friend wrote this loop and wants to know how many times the line count++ runs before running it:
``text count = 0 for i in 0 .. n-1: for j in 0 .. i-1: count = count + 1``
When i is 0 the inner loop does not run at all, and when i is 1 it runs once. Given n, print the final value of count. The loop is far too long to run for the biggest n, so work out the formula from the lesson instead.
**Constraints:** 0 <= n <= 2,000,000,000. The answer can exceed the range of a 32-bit integer.
Input. One integer n.
Output. One integer: the number of times `count` is increased.
Example 1 input
```
6
```
Output
```
15
```
Example 2 input
```
4
```
Output
```
6
```
Language
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); long n = sc.nextLong(); // your code here } }