sum = 0
i = 1
n = input('请输入计算1到n的和,n的数值:')
while i < int(n):
i = i + 1
print(sum)
i = 1
n = input('请输入计算1到n的和,n的数值:')
while i < int(n):
sum = sum + i
# 如果为2,就是偶数和
print(sum)
sum = sum + i
# 如果为2,就是偶数和