#include <stdio.h>
#include <string.h>

char s[25];
int cnt[26] = {0};

int main()
{
    scanf("%s", s);

    for (int i = 0; i < strlen(s); i ++ )
    {
        cnt[s[i] - 'a'] ++ ;
    }

    int min = 21;

    for (int i = 0; i <= 26; i ++ )
    {
        if (min > cnt[i] && cnt[i] != 0) min = cnt[i];
    }

    for (int i = 0; i < strlen(s); i ++ )
    {
        if (cnt[s[i] - 'a'] != min) printf("%c", s[i]);
    }

    return 0;
}