#include <bits/stdc++.h>
using namespace std;
struct Edge {
  int u, v, weight;
  bool operator<(const Edge& other) const { return weight < other.weight; }
};
int n;
int par[1005], qs[1005];
vector<pair<long long, int> > graph[1005];
int findRoot(int x) { return par[x] < 0 ? x : (par[x] = findRoot(par[x])); }
void merge(int a, int b) {
  a = findRoot(a);
  b = findRoot(b);
  if (a == b) return;
  if (par[b] < par[a]) swap(a, b);
  par[a] += par[b];
  par[b] = a;
}
bool sameSet(int a, int b) { return findRoot(a) == findRoot(b); }
int main() {
  int n, a, b, m, van = 0;
  long long cost = 0, c;
  bool pudo = false;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> qs[i];
  }
  cin >> m;
  priority_queue<pair<long long, int> > arcos;
  for (int i = 0; i < m; i++) {
    cin >> a >> b >> c;
    graph[a].push_back({-c, b});
    arcos.push({-c, b});
  }
  memset(par, -1, sizeof(par));
  van = 1;
  while (van < n && !arcos.empty()) {
    pair<long long, int> e = arcos.top();
    arcos.pop();
    if (!sameSet(0, e.second)) {
      cost += -e.first;
      van++;
      merge(0, e.second);
    }
  }
  if (van == n) {
    cout << cost << "\n";
  } else {
    cout << -1 << "\n";
  }
}
