#include <iostream>
#include <vector>
#include <map>
using namespace std;

int main() {
    string line;
    cin >> line;

    map<char, int> dict;

    for (char c : line) {
        dict[c]++;
    }

    vector<int> valuse;

// 获取 value 的列表 用于获取最小值
    for (auto p : dict) {
        valuse.push_back(p.second);
    }

    int num;
// 遍历获取最小值
    for (int i = 0; i < valuse.size() - 1; i++)
        num = min(valuse[i], valuse[i + 1]);

// 移除字符串中的最少出现的次数的字符
    string result = "";
    for (char c : line) {
        if (dict[c] != num)
            result += c;
    }

    cout << result << endl;
}