#include <iostream>
#include <string>
#include <unordered_map>
using namespace std;
int main() {
string str;
cin >> str;
// 统计字符频率
unordered_map<char, int> freq;
for (char c : str) {
freq[c]++;
}
// 找出最小频率
int minFreq = str.length();
for (auto& pair : freq) {
minFreq = min(minFreq, pair.second);
}
// 构建结果字符串
string result;
for (char c : str) {
if (freq[c] > minFreq) {
result += c;
}
}
cout << result << endl;
return 0;
}
import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
String str = sc.nextLine();
// 统计字符频率
Map<Character, Integer> freq = new HashMap<>();
for (char c : str.toCharArray()) {
freq.put(c, freq.getOrDefault(c, 0) + 1);
}
// 找出最小频率
int minFreq = str.length();
for (int count : freq.values()) {
minFreq = Math.min(minFreq, count);
}
// 构建结果字符串
StringBuilder result = new StringBuilder();
for (char c : str.toCharArray()) {
if (freq.get(c) > minFreq) {
result.append(c);
}
}
System.out.println(result.toString());
}
}
}
s = input()
# 统计字符频率
freq = {}
for c in s:
freq[c] = freq.get(c, 0) + 1
# 找出最小频率
min_freq = min(freq.values())
# 构建结果字符串
result = ''.join(c for c in s if freq[c] > min_freq)
print(result)