Nick's company employed n people. Now Nick needs to build a tree hierarchy of «supervisor-surbodinate» relations in the company (this is to say that each employee, except one, has exactly one supervisor). There are m applications written in the following form: «employee ai is ready to become a supervisor of employee bi at extra cost ci». The qualification qj of each employee is known, and for each application the following is true: qai > qbi. 

Would you help Nick calculate the minimum cost of such a hierarchy, or find out that it is impossible to build it.

Input

The first input line contains integer n (1 ≤ n ≤ 1000) — amount of employees in the company. The following line contains n space-separated numbers qj (0 ≤ qj ≤ 106)— the employees' qualifications. The following line contains number m (0 ≤ m ≤ 10000) — amount of received applications. The following m lines contain the applications themselves, each of them in the form of three space-separated numbers: ai, bi and ci (1 ≤ ai, bi ≤ n, 0 ≤ ci ≤ 106). Different applications can be similar, i.e. they can come from one and the same employee who offered to become a supervisor of the same person but at a different cost. For each application qai > qbi.

Output

Output the only line — the minimum cost of building such a hierarchy, or -1 if it is impossible to build it.

Examples

Input

4
7 2 3 1
4
1 2 5
2 4 1
3 4 1
1 3 5


Output

11


Input

3
1 2 3
2
3 1 2
3 1 3


Output

-1

Note

In the first sample one of the possible ways for building a hierarchy is to take applications with indexes 1, 2 and 4, which give 11 as the minimum total cost. In the second sample it is impossible to build the required hierarchy, so the answer is -1.
#include <bits/stdc++.h>
using namespace std;
int n, m;
long long arr[1002];
void initialize() {
  for (int i = 1; i <= n; ++i) arr[i] = 1e15;
}
int root(int x) {
  while (x != arr[x]) {
    arr[x] = arr[arr[x]];
    x = arr[x];
  }
  return x;
}
void union0(int x, int y) { arr[root(x)] = arr[root(y)]; }
int main() {
  cin >> n;
  int mlhoshLazma;
  for (int i = 1; i <= n; ++i) cin >> mlhoshLazma;
  initialize();
  cin >> m;
  for (int i = 0; i < m; ++i) {
    int x, y;
    long long z;
    cin >> x >> y >> z;
    arr[y] = min(arr[y], z);
  }
  int cnt = 0;
  long long mx = 0;
  long long cost = 0;
  for (int i = 1; i <= n; ++i) {
    if (arr[i] != 1e15) {
      cost += arr[i];
      mx = max(arr[i], mx);
    } else
      cnt++;
  }
  if (cnt == 0)
    cout << cost - mx;
  else if (cnt == 1)
    cout << cost;
  else
    cout << -1;
  return 0;
}
