#include <iostream>
#include <string>
using namespace std;

const int N = 30;
struct Node {
    int left;
    int right;
};

int lc[N], rc[N];

void dfs(int u) {
    if (u == 0) return; 
    cout << (char)(u + 'a' - 1);
    dfs(lc[u]); 
    dfs(rc[u]); 
}

int main() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        string s;
        cin >> s;
        int u = s[0] - 'a' + 1;
        if (s[1] != '*') lc[u] = s[1] - 'a' + 1;
        if (s[2] != '*') rc[u] = s[2] - 'a' + 1;
    }
    dfs(1);
    return 0;
}