#include <iostream>
#include <cstring>
#include <vector>
using namespace std;
struct stari
{
    int a, b;
    char c;
};
vector<stari> vec[1024];
int n, i, j, k,m;
stari nod;
stari finale[256];
void DFSTryHard(char sir[256], int x,int nr)
{
    int ok;
    for (int i = 0; i < vec[x].size(); i++)
    {
        ok = 0;
        if (k == nr + 1)
        {
            for (int j = 1; j <= m; j++)
            {
                if (vec[x][i].a == finale[j].a && vec[x][i].b == finale[j].b && vec[x][i].c == finale[j].c)
                {
                    ok = 1;
                    break;
                }
            }
        }
        if (ok == 1 && k == nr + 1)
        {
            sir[nr] = vec[x][i].c;
            sir[nr + 1] = NULL;
            cout << sir << '\n';
            return;
        }
        if (k > nr + 1)
        {
            sir[nr] = vec[x][i].c;
            sir[nr + 1] = NULL;
            if(vec[x][i].b!=-1)
                DFSTryHard(sir, vec[x][i].b, nr + 1);
        }
        if (k < nr + 1)
        {
            return;
        }
    }
}
int main()
{
    cin >> n;//numarul de stari, practic numarul de muchii
    for (i = 1; i <= n; i++)//citesti starile, capetele muchiei si litera de pe ea
    {
        cin >> nod.a >> nod.b >> nod.c;
        vec[nod.a].push_back(nod);
    }
    cin >> m;//numarul de stari finale
    for (i = 1; i <= m; i++)//citesti starile ca mai sus
    {
        cin >> finale[i].a >> finale[i].b >> finale[i].c;
    }
    cin >> k;//numarul de litere pe care vrei sa le aiba cuvantul tau
    char sir[256];
    DFSTryHard(sir, 1, 0);//un DFS TRY HARD care afiseaza solutiile
}