666

#include<bits/stdc++.h>
using namespace std;

vector<int> ve[129];
void dfs(int x) {
cout << char(x);
if (ve[x][0]) dfs(ve[x][0]);
if (ve[x][1]) dfs(ve[x][1]);
}
int main() {
int n;
cin >> n;
for (int i = 0; i < 129; i++) ve[i].resize(2);
int root;
for (int i = 0; i < n; i++) {
string s;
cin >> s;
if (i == 0) root = s[0];
if (s[1] != '') ve[s[0]][0] = s[1];
if (s[2] != '') ve[s[0]][1] = s[2];
}
dfs(root);
return 0;
}