Write a program to compute the sum of the terms of the series: 4 - 8 + 12 - 16 + 20 -

[chewey777]

#Write a program to compute the sum of the terms of the series: 4 - 8 + 12 - 16 + 20 -
24 + 28 - 32 + .... +/- n, where n is an input. Consider that n is always valid (which
means it follows the series pattern).

n = int(input("Enter n: "))
sum = 0
for i in range(4,n+4,4):
    sum += i - (i+2)
print("The sum of %s first terms is: %s"%(n,sum))

I want to know what I'm doing wrong