#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <string>
#include <vector>

using namespace std;

int main() {
    vector<char> v;
    freopen("decode.in.txt", "r", stdin);
    string input;
    cin >> input;
    fclose(stdin);
    int len = -1;
    for (int i = 0; i < input.size(); i++) {
        if (i == 0) {
            v.push_back(input[i]);
            len++;
        }
        else {
            if ((len >=0) && (v[len] == input[i])) {
                v.pop_back();
                len--;
            }
            else {
                v.push_back(input[i]);
                len++;
            }
        }
    }
    freopen("decode.out.txt", "w", stdout);
    for (int i = 0; i < v.size(); i++) {
        cout << v[i];
    }
    fclose(stdout);
    return 0;
}