I try this but total is not right. 
also 1-2+3-4  doesn't work while user give odd number.

N = int(input("N: "))
i=1
x=2
Sum1=0
Sum2=0
while i <= N and x <=N:
    print("+", i, "-", x, end=' ')
    i= i+2
    x= x+2
    Sum1=Sum1+i
    Sum2=Sum2+x
print("=", Sum1-Sum2)



Result
>>>
N: 4
+ 1 - 2 + 3 - 4 = -2

>>> ================================ RESTART ================================
>>>
N: 5
+ 1 - 2 + 3 - 4 = -2
>>>
 Here it prints only 4, should print upto 5(user's given value) and total is not valid.