Problem:
Score : 100 points

Problem Statement

Given is an integer r.

How many times is the area of a circle of radius r larger than the area of a circle of radius 1?

It can be proved that the answer is always an integer under the constraints given.

Constraints

1 \leq r \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

r

Output

Print the area of a circle of radius r, divided by the area of a circle of radius 1, as an integer.

Sample Input 1

2

Sample Output 1

4

The area of a circle of radius 2 is 4 times larger than the area of a circle of radius 1.

Note that output must be an integer - for example, 4.0 will not be accepted.

Sample Input 2

100

Sample Output 2

10000

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<math.h>
int main(void){
  int n,j;
  scanf("%d",&n);
  int a[n],b[n],i;
  double ans=0;
  for(i=0;i<n;i++){
  scanf("%d%d",&a[i],&b[i]);
  }
  for(i=0;i<n;i++){
    for(j=i+1;j<n;j++){
       ans+=sqrt(pow(a[i]-a[j],2)+pow(b[i]-b[j],2));
    }
  }
  printf("%f",ans*2/n);
  return 0;
}