#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define MOD 998244353
#define MAX 6020202
map<pii, int> mp;
pii edges[MAX];
int W[MAX];
vector<int> nxt[MAX];
vector<int> gph[MAX];
vector<pii> adj[MAX];
int eloc[MAX];
int cnt;
int ch[MAX][2];
int init(int v, int s, int e, int loc) {
	if (s == e) {
		adj[loc].emplace_back(gph[v][s], W[gph[v][s]]);
		return loc;
	}
	int m = s + e >> 1;
	adj[loc].emplace_back(ch[loc][0] = init(v, s, m, ++cnt), 0);
	adj[loc].emplace_back(ch[loc][1] = init(v, m + 1, e, ++cnt), 0);
	return loc;
}
void add(int v, int edge, int s, int e, int l, int r, int loc) {
	if (e < l || r < s) return;
	if (l <= s && e <= r) {
		adj[edge].emplace_back(loc, 0);
		return;
	}
	int m = s + e >> 1;
	add(v, edge, s, m, l, r, ch[loc][0]);
	add(v, edge, m + 1, e, l, r, ch[loc][1]);
}
ll dist[MAX];
int vis[MAX];
signed main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int N, M;
	cin >> N >> M;
	int i, a, b, c;
	for (i = 1; i <= M; i++) {
		cin >> a >> b;
		eloc[i] = gph[a].size();
		gph[a].push_back(i);
		edges[i] = pii(a, b);
		cin >> W[i];
		mp[pii(a, b)] = i;
	}
	cnt = N + M;
	for (i = 1; i <= N; i++) {
		if (gph[i].empty()) continue;
		int d = gph[i].size();
		init(i, 0, d - 1, i + M);
	}
	int K;
	cin >> K;
	for (i = 1; i <= K; i++) {
		cin >> a >> b >> c;
		int e1, e2;
		e1 = mp[pii(a, b)];
		e2 = mp[pii(b, c)];
		nxt[e1].push_back(eloc[e2]);
	}
	for (i = 1; i <= M; i++) {
		int nv = edges[i].second;
		if (nxt[i].empty()) adj[i].emplace_back(nv + M, 0);
		else {
			sort(nxt[i].begin(), nxt[i].end());
			int p = -1;
			for (auto l : nxt[i]) {
				if (p + 1 < l) add(nv, i, 0, (int)gph[nv].size() - 1, p + 1, l - 1, nv + M);
				p = l;
			}
			if (p + 1 < gph[nv].size()) add(nv, i, 0, (int)gph[nv].size() - 1, p + 1, (int)gph[nv].size() - 1, nv + M);
		}
	}
	for (i = 1; i <= cnt; i++) dist[i] = 1e18;
	typedef pair<ll, int> pli;
	priority_queue<pli, vector<pli>, greater<pli>> pq;
	for (i = 1; i <= M; i++) {
		if (edges[i].first == 1) {
			dist[i] = W[i];
			pq.emplace(W[i], i);
		}
	}
	while (pq.size()) {
		auto t = pq.top().second;
		pq.pop();
		if (vis[t]) continue;
		vis[t] = 1;
		for (auto& [v, w] : adj[t]) {
			if (dist[v] > dist[t] + w) {
				dist[v] = dist[t] + w;
				pq.emplace(dist[v], v);
			}
		}
	}
	ll ans = 1e18;
	for (i = 1; i <= M; i++) if (edges[i].second == N) ans = min(ans, dist[i]);
	if (ans <= 1e17) cout << ans;
	else cout << -1;
}