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

using namespace std;
using i64 = long long;

using A = array<int, 3>;

A make(int a, int b, int c) {
    A res;
    res[0] = a;
    res[1] = b;
    res[2] = c;
    return res;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    vector<set<pair<int, i64>>> out(n);
    for (int i = 0; i < m; i++) {
        int a, b;
        i64 w;
        cin >> a >> b >> w;
        a--, b--;
        out[a].emplace(b, w);
    }
    set<A> banned;
    int k;
    cin >> k;
    for (int i = 0; i < k; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--, c--;
        banned.emplace(make(a, b, c));
    }
    vector<vector<pair<i64, int>>> in(n);
    vector<i64> dist(n, 1e18);
    in[0].emplace_back(0, -1);
    for (int i = 0; i < n; i++) {
        auto& v = in[i];
        sort(v.begin(), v.end());
        vector<pair<int, int>> er;
        for (auto& [c, from] : v) {
            dist[i] = min(dist[i], c);
            for (auto& [to, w] : out[i]) {
                if (banned.count(make(from, i, to))) continue;
                in[to].emplace_back(c + w, i);
                er.emplace_back(to, w);
            }
            for (auto p : er) out[i].erase(p);
            er.clear();
        }
    }
    i64 ans = dist[n - 1];
    if (ans == 1e18) ans = -1;
    cout << ans << endl;
}