include <bits/stdc++.h>

using namespace std;
bool check_alphabet[26] = {false};
void missing_alphabet(string s){
for (int i = 0; i < s.length(); i++){
int k = s[i] - 'a';
check_alphabet[k] = true;
}
}
void print_missing_alphabet(){
for (int i = 0; i < 26; i++){
if (check_alphabet[i] == false){
cout << char(i + 'a') << " ";
}
}
}
int main (){
string ch;
getline(cin,ch);
missing_alphabet(ch);
print_missing_alphabet();
return 0;
}