def one(n):
    k=n//3
    return 3*k*(k+1)//2-2*k
def two(n):
    k=n//3
    return 3*k*(k+1)*(2*k+1)//2-3*k*(k+1)+k
def three(n):
    k=n//3
    return 27*(k*(k+1)//2)**2

N=int(input())
if N%3==0:
    print(one(N)+two(N)+three(N))
elif N%3==1:
    print(one(N)+two(N)+three(N)+N)
else:
    print(one(N)+two(N)+three(N)+N+N**2-1)