#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll MAX = 1e5+10;
const ll ZERO = 0;

#define endl '\n'
#define dokme(x) cout << x ;  return(0);
#define migmig ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

stack < char > stk;

int main(){
    migmig;
    stk.push('.');
    char c[200001];
    cin >> c;
    int n=strlen(c);
    for (int i =0; i < n ; i ++ ){
        if (stk.top()!=c[i]){
            stk.push(c[i]);
        }
        else{
            stk.pop();
        }
    }
    n=stk.size()-1;
    memset(c,0,sizeof(c));
    for (int i = 0 ; i<n ; i ++ ){
        c[n-i-1]=stk.top();
        stk.pop();
    }
    cout << c;
}