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: Runtime Error)

#include<stdio.h>
#include<math.h>
#include<stdlib.h>

int main()
{
  long long int x,y;
  long long int k,ka,kb;
  long long int ans;
  int i;

  scanf("%lld %lld",&x,&y);

  long long int a,b;

  if((2*x-y)%3==0&&((-1)*(x-2*y))%3==0)
  {
    a=(2*x-y)/3;
    b=(-1)*(x-2*y)/3;

    printf("%lld %lld\n",a,b);

    k=1;
    ka=1;
    kb=1;

    for(i=0;i<(a+b);i++)
    {
      k=k*(i+1);
    }
    for(i=0;i<a;i++)
    {
      ka=ka*(i+1);
    }
    for(i=0;i<b;i++)
    {
      kb=kb*(i+1);
    }
    /*printf("%lld %lld %lld\n",k,ka,kb);*/
    ans=k/(ka*kb);
    ans=ans%1000000007;
  }
  else
  {
    ans=0;
  }
  printf("%lld",ans);

  return 0;
}