while True:
    try:
        n=input()
        l=[]
        for i in n[::-1]:
            if i not in l:
                l.append(i)
        print(''.join(l))
    except:
        break

# s=input()[::-1]
# a=[]
# for i in s:
#     if i not in a:
#         a.append(i)
#         print(i,end='')