#include <iostream>
#include <sstream>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <numeric>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <deque>

using namespace std;
#define ll long long
void sherry()
{
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}
/*bool comp(pair<int, int> a, pair<int, int> b)
{
    return a.second < b.second;
}*/
int main()
{
    sherry();
    stack<char> s;
    string c;
    getline(cin, c);
    s.push(c[0]);
    for (ll i = 1; i < c.size(); i++)
    {
        if (c[i] == s.top())
            s.pop();
        else
        {
            s.push(c[i]);
        }
    }
    for (size_t i = 0; !s.empty(); i++)
    {
        cout << s.top();
        s.pop();
    }
    return 0;
}