#include <iostream>
// write your code here......
#include <set>
using namespace std;
int main() {
char str[100] = { 0 };
cin.getline(str, sizeof(str));
// write your code here......
set<char> s;
for (int i = 0; str[i] != '\0'; i++) {
s.insert(str[i]);
}
for (auto iter = s.begin(); iter != s.end(); iter++) {
cout << *iter;
}
return 0;
}



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