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 Python (3.4.3) (judge verdict: Runtime Error)

#Beginner COnetst 145 /2019/11/16
#Probrem A
#import math
from operator import mul
from functools import reduce

DEBUG = 0

def combinations_count(n, r):
    r = min(r, n - r)
    numer = reduce(mul, range(n, n - r, -1), 1)
    denom = reduce(mul, range(1, r + 1), 1)
    return numer // denom

def calc(x,y):
    if (x*2-y)%3 != 0 or (y*2-x)%3 != 0: return 0
    m = (x*2-y)//3
    n = (y*2-x)//3
    if m <= 0 or n <= 0:return 0
    return combinations_count(m+n,m)

X,Y = list(map(int, input().split()))

if DEBUG:print(X,Y)

print(calc(X,Y)%(10**9+7))