题解 | 牛牛学数列
牛牛学数列
https://www.nowcoder.com/practice/0b97367cd2184c12a0e02f7c223aee11
#奇数加，偶数减
a=int(input())
b=0
for x in range(1,a+1):
if x%2 != 0:
b+=x
else:
b-=x
print(b)
'''
n = int(input())
ji = 0
ou = 0
for i in range(1, n+1):
if i % 2 == 0:
ou += i
else:
ji += i
print(ji-ou)
'''
