Given a number N, print sum of all even numbers from 1 to N.

##### Input Format :

Integer N

##### Output Format :

Required Sum

##### Sample Input 1 :

6

##### Sample Output 1 :

12

##### Solution :

```
/*
Pre-requisite to solve this problem:
In this question, we have to find sum of all even numbers till n. To take sum of all the even numbers, we have to take a variable and initialize it to zero. Let us name this variable as sum.
Following code is used to add 2 to sum variable and update it to the same sum variable:
sum = sum + 2
Hint to solve this problem: We will have to loop on even numbers only and add the even numbers to the same sum variable, described above.
*/
import java.util.Scanner;
public class Solution {
public static void main(String[] args) {
/* Your class should be named Solution.
* Read input as specified in the question.
* Print output as specified in the question.
*/
Scanner input = new Scanner(System.in);
int n = input.nextInt();
int i = 2;
int sum = 0;
while (i <= n){
sum = sum+i;
i = i + 2;
}
System.out.println(sum);
}
}
```