#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <algorithm>
#include <numeric>
#include <functional>
#include <set>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <climits>
#include <fstream>
#include <time.h>

#define ll long long
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define FOE(i,a) for(auto i : a)
#define ALL(c) (c).begin(), (c).end()
#define DUMP(x)  cerr << #x << " = " << (x) << endl;
#define SUM(x) std::accumulate(ALL(x), 0L)
#define EPS 1e-14

using namespace std;

struct ErasingCharacters {
    string s;
    string simulate(string _s) {
        s = _s;

        FOR(i, 1, s.size()) {
            if (s[i - 1] == s[i]) {
                return simulate(s.erase(i - 1, 2));
            }
        }

        return s;
    }
};