from collections import Counter

# 输入字符串
s = input()

# 统计字符出现次数
freq = Counter(s)

# 找出最少出现的次数
min_freq = min(freq.values())

# 创建删除最少出现字符后的新字符串
result = ''.join([char for char in s if freq[char] > min_freq])

# 输出结果
print(result)