#include<iostream>
using namespace std;

int main() {
 // Initialize array of 5 letters
 char letters[5];

 // Receive 5 letters from user
 cout << "Enter 5 letters: ";
 for(int i=0; i<5; i++)
   cin >> letters[i];

 // Print letters in reverse order
 for(int i=4; i>=0; i--)
   // If letter repeats in input, don't repeat on output
   if(i==4 || letters[i]!=letters[i+1])
     cout << letters[i];

 // Print new line at end
 cout << endl;

 return 0;
}