题解 | #提取不重复的整数#

while True:
    try:
        list1=list(input())
        a=len(list1)
        j=a-1
        list2=[]
        for i in range(a):
            if list1[j] in list2:
                j-=1
            else:
                list2.append(list1[j])
                j-=1
        k=0
        for i in range(len(list2)):
            print(list2[k],end='')
            k+=1
    except:
        break