/* -*- coding: utf-8 -*-
 *
 * 2477.cc:  No.2477 Drifting - yukicoder
 */

#include<cstdio>
#include<vector>
#include<unordered_map>
#include<unordered_set>
#include<algorithm>
#include<utility>
 
using namespace std;

/* constant */

const int MAX_N = 200000;
const int MAX_M = 200000;
const int MAX_GN = MAX_N + MAX_M;
const long long LINF = 1LL << 62;

/* typedef */

using ll = long long;
using vl = vector<ll>;
using pii = pair<int,int>;
using vpii = vector<pii>;
using usi = unordered_set<int>;
using vusi = vector<usi>;
using umii = unordered_map<int,int>;

/* global variables */

vpii nbrs[MAX_N];
umii exis[MAX_N];
vusi excs[MAX_N];
vl dp[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);

  for (int i = 0; i < m; i++) {
    int u, v, w;
    scanf("%d%d%d", &u, &v, &w);
    u--, v--;
    nbrs[u].push_back({v, w});
  }

  int k;
  scanf("%d", &k);

  for (int i = 0; i < k; i++) {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    a--, b--, c--;

    auto mit = exis[b].find(a);
    int j = 0;
    if (mit != exis[b].end()) j = mit->second;
    else j = exis[b][a] = exis[b].size();

    if (j < excs[b].size()) excs[b][j].insert(c);
    else {
      usi cs; cs.insert(c);
      excs[b].push_back(cs);
    }
  }

  for (int u = 0; u < n; u++) {
    excs[u].push_back(usi());
    dp[u].assign((int)excs[u].size(), LINF);
  }

  dp[0][0] = 0;
  for (int u = 0; u < n; u++)
    for (int i = 0; i < excs[u].size(); i++)
      if (dp[u][i] < LINF) {
	for (auto [v, w]: nbrs[u]) {
	  if (! excs[u][i].empty() &&
	      excs[u][i].find(v) != excs[u][i].end())
	    continue;

	  auto mit = exis[v].find(u);
	  int j =
	    (mit != exis[v].end()) ? mit->second : exis[v].size();
	  dp[v][j] = min(dp[v][j], dp[u][i] + w);
	}
      }

  ll mind = *min_element(dp[n - 1].begin(), dp[n - 1].end());
  printf("%lld\n", (mind < LINF) ? mind : -1LL);
  
  return 0;
}