#include 
#include 

int main() {
    char str[21];
    int hash[26] = {0};
    int i = 0, min = 21;
    scanf("%s", str);
    while (str[i] != '\0') {
        hash[str[i]-'a']++;
        i++;
    }
    for (int j = 0; j < 26; j++) {
        if (hash[j] != 0) {
            min = min > hash[j] ? hash[j] : min;
        }
    }
    int k = 0;
    while (str[k] != '\0') {
        if (hash[str[k]-'a'] != min) {
            printf("%c", str[k]);
        }
        k++;
    }
    return 0;
}