#include <bits/stdc++.h>
using namespace std;
pair<long long, pair<long long, long long> > edge[100001];
long long parent[1001];
long long visited[1001];
long long find_set(long long node) {
  if (parent[node] == node)
    return node;
  else
    return find_set(parent[node]);
}
void union_set(long long src, long long des) { parent[src] = parent[des]; }
int main() {
  long long n, m, ans = 0;
  cin >> n;
  long long q[n + 1];
  for (long long i = 1; i <= n; i++) {
    cin >> q[i];
    parent[i] = i;
  }
  cin >> m;
  for (long long i = 0; i < m; i++) {
    long long x, y, c;
    cin >> x >> y >> c;
    edge[i] = make_pair(c, make_pair(x, y));
  }
  sort(edge, edge + m);
  for (long long i = 0; i < m; i++) {
    long long src, des, val;
    src = edge[i].second.first;
    des = edge[i].second.second;
    val = edge[i].first;
    long long x = find_set(src);
    long long y = find_set(des);
    if (x != y && visited[des] == 0) {
      ans += val;
      union_set(x, y);
      visited[des] = 1;
    }
  }
  for (long long i = 1; i <= n; i++) {
    if (find_set(i) != find_set(1)) {
      cout << "-1" << endl;
      return 0;
    }
  }
  cout << ans << endl;
}
