题解 | #提取不重复的整数#

def tm009():
    #读取输入
    s=input()
    s=s[::-1]
    s2=''
    #去重
    for i in s:
        if i in s2:
            continue
        s2=s2+i
    print(s2)
if __name__ == '__main__':
    tm009()