#include <bits/stdc++.h>
using namespace std;
const int N = 10005;
struct edge {
  int u, v, c, pre;
} E[N * 2];
int head[N], cnt;
void add_edge(int u, int v, int c) {
  E[cnt].u = u;
  E[cnt].v = v;
  E[cnt].c = c;
  E[cnt].pre = head[u];
  head[u] = cnt++;
}
int res;
bool vis[N / 10 + 5];
int Set[1005];
int Find_Set(int x) {
  if (Set[x] == x) return x;
  return Set[x] = Find_Set(Set[x]);
}
void Union_Set(int x, int y) { Set[Find_Set(x)] = Find_Set(y); }
void dfs(int u) {
  int small = 10000000, pos = -1;
  for (int i = head[u]; i != -1; i = E[i].pre) {
    int v = E[i].v;
    int c = E[i].c;
    if (c < small) {
      small = c;
      pos = i;
    }
  }
  if (pos != -1) {
    Union_Set(E[pos].v, u);
    res += small;
  }
}
int val[N / 10 + 5];
int main() {
  int n;
  while (~scanf("%d", &n)) {
    memset(head, -1, sizeof(head));
    memset(vis, false, sizeof(vis));
    for (int i = 1; i <= n; i++) Set[i] = i;
    cnt = 0;
    for (int i = 1; i <= n; i++) scanf("%d", val + i);
    int m;
    scanf("%d", &m);
    while (m--) {
      int u, v, c;
      scanf("%d%d%d", &u, &v, &c);
      if (v != u) add_edge(v, u, c);
    }
    res = 0;
    for (int i = 1; i <= n; i++) {
      dfs(i);
    }
    set<int> q;
    q.clear();
    for (int i = 1; i <= n; i++) q.insert(Set[Find_Set(i)]);
    if (q.size() > 1)
      printf("%d\n", -1);
    else
      printf("%d\n", res);
  }
  return 0;
}
