s=0

t=1

for n in range(1,21):

    t*=n

    s+=t

print('1!+2!+3!+.....+20!=%d'%s)

def palin(n):

    next=0

    if n<=1:

        next=input()

        print()

        print(next)

    else:

        next=input()

        palin(n-1)

        print(next)

i=5

palin(i)

print()

num = int(input('input a number：'))

a=num//10000%10

b=num//1000%10

c=num//100%10

d = num//10%10

e= num%10

a=num/10000

b=num%10000/1000

c=num%1000/100

d=num%100/10

e=num%10

if a!=0:

    print('there are 5',e ,d ,c,b,a)

elif b!=0:

    print('there are 4',d ,c,b,a)

elif c!=0:

    print('there are 3', e, d, c)

elif d!=0:

    print('there are 2',  e, d)

else:

    print('there are 1',  e)

#第二种方法

num =input('输入一个不超过5位的正整数：')

l=len(num)

print('这个数是',l,'位数')

n=num[::-1] #通过索引切片，逆序打印出数字

for i in n:

    print(i)

a = input("输入一串数字: ")

b = a[::-1]

if a == b:

    print("%s 是回文"% a)

else:

    print("%s 不是回文"% a)

Num = input('please input a number:')

if Num[:] == Num[::-1]:

      print('True')

else:

       print('False')

#

letter = input("please input:")

# while letter  != 'Y':

if letter == 'S':

    print('please input second letter:')

    letter = input("please input:")

    if letter == 'a':

        print('Saturday')

    elif letter == 'u':

        print('Sunday')

    else:

        print('data error')

elif letter == 'F':

    print('Friday')

elif letter == 'M':

    print('Monday')

elif letter == 'T':

    print('please input second letter')

    letter = input("please input:")

    if letter == 'u':

        print('Tuesday')

    elif letter == 'h':

        print('Thursday')

    else:

        print('data error')

elif letter == 'W':

    print('Wednesday')

else:

    print('data error')

num=[]

i=2

for i in range(2,100):

    for j in range(2,i):

        if i%j==0:

            break

    else:

        num.append(i)

print(num)

list=[]

for i in range(10):

    a = input('请输入整数：')

    list.append(a)

print(list)

list.sort()

print(list)

list=[]

for i in range(10):

    print('输入第%d个整数'%i)

    a=input()

    list.append(a)

print(list)

for i in  range(9):

    min_index=i

    for j in range(i+1,10):

        if list[j]<list[min_index]:

          list[min_index],list[j]=list[j],list[min_index]

    print(list)