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.

Constraints

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

Examples

Input:
n = 4

Expected output:
expected = 70

Input:
long long n = 4;

Expected output:
long long expected = 70;

Input:
long n = 4;

Expected output:
long expected = 70;

Input:
n = 1

Expected output:
expected = 0

Input:
long long n = 1;

Expected output:
long long expected = 0;

Input:
long n = 1;

Expected output:
long expected = 0;

References

This challenge is adapted for CodeUtility. Follow the statement and constraints above.

• #6 Sum Square Difference
• Difference of Squares