挑选字符串中从右端开始数的五个不重复字母（出现多个，只挑出一次）

X = 0
newlist = []
mystr = str(input('give string: '))
mylist = list(mystr)
mylist.reverse()
print(mylist)
while X<5:
    for i in mylist:
        if mylist.count(i)== 1:
            newlist.append(i)
            X += 1
        else:
            continue
print(newlist)X = 0
newlist = []
mystr = str(input('give stri