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.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
import java.util.Arrays;

/**
 * @author fancy
 * @date 2020/11/20 9:55
 */
public class Main {
    static int n,m;
    static long ans;
    static int a[] = new int[1010];
    static int vis[] = new int[1010];
    static To b[] = new To[10010];
    public static void main(String[] args) throws IOException {
        StreamTokenizer re = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
        re.nextToken(); n = (int)re.nval;
        for(int i = 1;i <= n;i++){
            re.nextToken();
            a[i] = (int)re.nval;
        }
        re.nextToken(); m = (int)re.nval;
        for(int i = 1;i <= m;i++){
            b[i] = new To();
            re.nextToken(); b[i].a = (int)re.nval;
            re.nextToken(); b[i].b = (int)re.nval;
            re.nextToken(); b[i].c = (int)re.nval;
        }
        Arrays.sort(b,1,m+1);
        for(int i = 1;i <= m;i++){
            if(a[b[i].a] > a[b[i].b] && vis[b[i].b] == 0){
                vis[b[i].b] = 1;
                ans += b[i].c;
            }
        }
        int cnt = 0;
        for(int i = 1;i <= n;i++)
            if(vis[i] == 0) cnt++;
        if(cnt != 1)
            System.out.println(-1);
        else
            System.out.println(ans);
    }
}
class To implements Comparable<To>{
    int a,b,c;
    @Override
    public int compareTo(To o) {
        return this.c-o.c;
    }
}