用python编阶层

# 阶层
sum = 1
n = 1
a =int( input("输入一个数："))
while n<=a:
    sum = sum*n
    n +=1
print(sum)

# 阶层的和
num = 0
n = 1
a = int(input("输入一个数字:"))
while n<=a:
    m = 1
    sum = 1
    while m<=n:
        sum *= m
        m += 1
    n+=1
    num += sum

print(num)