#include <iostream>
#include<string.h>
using namespace std;
int main() {
char ch[100];
cin>>ch;
int arr[26]={0};
for(int i =0;i<12;i++){
if(arr[ch[i]-'a']==0){
arr[ch[i]-'a']++;
cout<<ch[i];
}
}
return 0;
}
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