#1.5 使用while循环实现输出2-3+4-5+6.....+100的和

#方法1
i = 2
sum1 = 0
while i <= 100:
    sum1 += (-1)**i * i
    i += 1

#方法2
sum2 = 0
for j in range(2,101):sum2 += (-1)**j * j

print(sum1,sum2)