#include <vector>
#include <iostream>
#include <map>
#include <set>
#include <algorithm>

using namespace std;

int dfs(int passId, int l, int k, const int p,
        const map<int, pair<vector<pair<int, int>>, vector<pair<int, int>>>>& fromEachPassToDriverAndOtherPass,
        set<int>& used)
{
    int min_price = k;
    used.insert(passId);
    const auto& pass = fromEachPassToDriverAndOtherPass.at(passId);
    const auto& toDrivers = pass.first;
    const auto& toOthersPass = pass.second;
    for (const auto& toDriver : toDrivers)
    {
        if (toDriver.second + l < p)
            min_price -= (p - toDriver.second - l);
    }
    for (const auto& toOtherPass : toOthersPass)
    {
        if (toOtherPass.second + l < p && used.find(toOtherPass.first) == used.end())
        {

            min_price = min(min_price,
                            dfs(toOtherPass.first, l + toOtherPass.second, min_price, p, fromEachPassToDriverAndOtherPass,
                                used));
        }
    }
    return min_price;
}

int main()
{
    int m, n, p, k, s, t;
    cin >> m >> n >> p >> k >> s;
    map<int, pair<vector<pair<int, int>>, vector<pair<int, int>>>> fromEachPassToDriverAndOtherPass;
    for (int i = 0; i < s; ++i)
    {
        int t1, t2, t3;
        cin >> t1 >> t2 >> t3;
        fromEachPassToDriverAndOtherPass[t2].first.emplace_back(t1, t3);
    }
    cin >> t;
    for (int i = 0; i < t; ++i)
    {
        int t1, t2, t3;
        cin >> t1 >> t2 >> t3;
        fromEachPassToDriverAndOtherPass[t1].second.emplace_back(t2, t3);
        fromEachPassToDriverAndOtherPass[t2].second.emplace_back(t1, t3);
    }
    int min_price = k;
    for (const auto& pass : fromEachPassToDriverAndOtherPass)
    {
        int passId = pass.first;
        set<int> used;
        min_price = min(min_price, dfs(passId, 0, k, p, fromEachPassToDriverAndOtherPass, used));
        if (min_price <= 1)
        {
            cout << 1;
            return 0;
        }
    }
    cout << min_price;
    return 0;
}