#include <bits/stdc++.h>

//define fin cin
//define fout cout

#define F first
#define S second
#define pii pair < int , int >

using namespace std;

typedef long long ll;

const int nmax = 1e6 + 10;

int n , i;
char s[nmax];

string ans , act;

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("input.in","r",stdin);
    freopen("output.out","w",stdout);
    #endif // ONLINE_JUDGE

    /*
    ifstream fin("input.in");
    ofstream fout("output.out");
    */


    for (i = 1; ; ++i)
    {
        gets(s);

        if (feof(stdin)) break;

        act = s;
        if (act.size() == 0) break;

        if (i == 1) ans = s;
        else if (ans != s) ans += s;
    }

    cout << ans;

    return 0;
}