#define _CRT_SECURE_NO_WARNINGS

#include <iostream>
#include <cmath>
#include <algorithm>
#include <set>
#include <vector>
#include <string>
#include <cstdlib>

using namespace std;

void optimization() {
     cin.tie(nullptr);
     ios_base::sync_with_stdio(false);
}


int main() {
     optimization();

     string s;
     int k = -1;
     cin >> s;
     char c[200000];

     for (char & i : c) {
          i = ' ';
     }

     for (char i : s) {
          if (k > -1) {
               if (c[k] == i) {
                    c[k] = ' ';
                    k--;
               } else {
                    k++;
                    c[k] = i;
                    continue;
               }
          }
          else {
               k++;
               c[k] = i;
          }
     }
     for (char i : c) {
          if (i != ' ') {
               cout << i;
          }
     }

     return 0;
}