#include <bits/stdc++.h>
using namespace std;
int n, m;
int par[1001];
priority_queue<pair<int, pair<int, int> >, vector<pair<int, pair<int, int> > >,
               greater<pair<int, pair<int, int> > > >
    pq;
bool hasSuper[1001], visited[1001];
vector<int> g[1001];
int findRepresentative(int x) {
  if (par[x] == x) {
    return x;
  } else {
    par[x] = findRepresentative(par[x]);
    return par[x];
  }
}
void dfs(int x) {
  if (!visited[x]) {
    visited[x] = true;
    for (int i : g[x]) {
      dfs(i);
    }
  }
}
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    int x;
    cin >> x;
    par[i] = i;
    hasSuper[i] = false;
  }
  cin >> m;
  for (int i = 1; i <= m; i++) {
    int a, b, c;
    cin >> a >> b >> c;
    pq.push(make_pair(c, make_pair(a, b)));
  }
  long long int ans = 0;
  while (!pq.empty()) {
    int nowCost = pq.top().first;
    pair<int, int> node = pq.top().second;
    int nodeA = node.first;
    int nodeB = node.second;
    pq.pop();
    int parA = findRepresentative(nodeA);
    int parB = findRepresentative(nodeB);
    if (parA != parB && !hasSuper[nodeB]) {
      par[parA] = parB;
      ans += nowCost;
      hasSuper[nodeB] = true;
      g[nodeA].push_back(nodeB);
      g[nodeB].push_back(nodeA);
    }
  }
  dfs(1);
  for (int i = 1; i <= n; i++) {
    if (!visited[i]) {
      cout << -1 << endl;
      return 0;
    }
  }
  cout << ans << endl;
}
