#include<iostream>
#include<cstdio>
#include<cstring>
#include<map>
#include<string>
using namespace std;
string s,S;
map<char,int>mp;
void strcompress(string s){
	int count=0;
	for(int i=0;i<s.size();i++){
		mp[s[i]]++;
		if(mp[s[i]]==1||mp[s[i]]==3||mp[s[i]]==6)S+=s[i];
		if(s[i]==' ')S+=s[i];
	}
	cout<<S<<endl;
}
int main(){
	getline(cin,s);
	strcompress(s);
	return 0;
}