Difference of Squares

Using the integers from 1 through n, calculate two quantities: first add the integers and square the result; separately square each integer and add those squares. Return the first quantity minus the second.

Implement difference_of_squares(n).

Input

n: The last integer to include.

Output

Return square-of-sum minus sum-of-squares.

Contraintes

0 ≤ n ≤ 50,000. For n = 0, both sums are 0. All required values fit signed 64-bit integers.

Exemples

Entrée :
n = 4

Sortie attendue :
expected = 70

Entrée :
long long n = 4;

Sortie attendue :
long long expected = 70;

Entrée :
long n = 4;

Sortie attendue :
long expected = 70;

Entrée :
n = 1

Sortie attendue :
expected = 0

Entrée :
long long n = 1;

Sortie attendue :
long long expected = 0;

Entrée :
long n = 1;

Sortie attendue :
long expected = 0;

Références

Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.

• #6 Sum Square Difference
• Difference of Squares