#include <iostream>
using namespace std;
int main() {
string s, r = "";
cin >> s;
for (int i = 0; i < s.size(); i++) {
bool f = false;
for (int j = 0; j < r.size(); j++) {
if (s[i] == r[j]) {
f = true;
break;
}
}
if (!f) r += s[i];
}
cout << r;
return 0;
}
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