# hashmap解法:分组计数,排除掉最小值的字母
# 时间:单次循环O(n).空间:k个哈希表字符,l个字符存在res,所以O(k+l)
while True:
    try:
        str1=input()
        hashmap,res={},""
        for i in str1:
            if i not in hashmap:
                hashmap[i]=1
            else:
                hashmap[i]+=1
        min_value=min(hashmap.values())
        for i in str1:
            if hashmap[i] != min_value:
                res+=i
        print(res)
    except:
        break