#include<bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    while(cin >> s) {
        int c[300] = {0};
        for(int i = 0; i < s.size(); i++) {
            c[s[i]] += 1;
        }
        int minn = 30;
        for(int i = 0; i < 300; i++) {
            if(c[i] != 0 && c[i] <= minn) minn = c[i];
        }
        //cout << minn;
        string ans = "";
        for(int i = 0; i < s.size(); i++) {
            if(c[s[i]] != minn && c[s[i]] != 0) ans += s[i];
        }
        cout << ans << endl;
    }
    return 0;
}