This is a sample problem to demonstrate the runtimes of different solutions with different time complexities.

Calculate the sum of integers in the range \([1, N]\).

Input Specification

The first line of the input will contain an integer \(N\) \((1 \le N \le 10^9)\).

Output Specification

Output the sum of integers in the range \([1, N]\). For C++ and Java users make sure you use long long or long to prevent integer overflow.

Sample Input

4

Sample Output

10

Sample Explanation

The sum is \(1 + 2 + 3 + 4 = 10\).