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.

Restricciones

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

Ejemplos

Entrada:
n = 4

Salida esperada:
expected = 70

Entrada:
long long n = 4;

Salida esperada:
long long expected = 70;

Entrada:
long n = 4;

Salida esperada:
long expected = 70;

Entrada:
n = 1

Salida esperada:
expected = 0

Entrada:
long long n = 1;

Salida esperada:
long long expected = 0;

Entrada:
long n = 1;

Salida esperada:
long expected = 0;

Referencias

Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.

• #6 Sum Square Difference
• Difference of Squares