题解 | #提取不重复的整数#

# num = int(input())
# new_num = 0
# dic_list = []
# while num:
#     if num%10 not in dic_list:
#         dic_list.append(num%10)
#         new_num = new_num*10 + num%10
#         num = num // 10
#     else:
#         num = num // 10
# print(new_num)

num = input()
num = num[::-1]
new_num = []
for i in num:
    if i in new_num:
        continue
    else:
        new_num.append(i)
        print(i,end='')