#include <bits/stdc++.h>

using namespace std;
using LL = long long;
using ULL = unsigned long long;
using VI = vector<int>;
using VL = vector<LL>;
using PII = pair<int, int>;
using PLL = pair<LL, LL>;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define MP make_pair
#define PB push_back
#define EB emplace_back
#define F first
#define S second
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define FILL(a, b) memset(a, b, sizeof(a))

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	string s;
	cin >> s;
	s += '!';
	string t = "", t2 = "";
	vector<string> v1, v2;
	FOR (i, 0, SZ(s))
	{
		if (s[i] == '!')
		{ 
			if (!v1.empty() && v1.back() == t)
			{
				t = t2 = "";
				continue;
			}
			else if (SZ(v1) > 1 && v1[SZ(v1) - 2] == t)
			{
				v1.pop_back();
				v2.pop_back();
			}
			else
			{
				v1.push_back(t);
				v2.push_back(t2);
			}
			t = t2 = "";
		}
		else
		{
			t2 += s[i];
			t += tolower(s[i]);
		}
	}
	FOR (i, 0, SZ(v2))
	{
		if (i) cout << '!';
		cout << v2[i];
	}
	cout << '\n';
	
}