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.util.Arrays;

public class Main {

	InputStreamReader inp = new InputStreamReader(System.in);
	BufferedReader in = new BufferedReader(inp);
	boolean test = false;

	String[] inData = { 
			
//			"1",
//			"2000 1000000000",
//			"0 10",
//			"1 10",
//			"1 10"
			
		"4",
		"7 2 3 1",
		"4",
		"1 2 5",
		"2 4 1",
		"3 4 1",
		"1 3 5"
	};
	
	int[][] vals;
	
	public Main() throws Throwable {
		
		int nr = readInt();
		
		int[] qs = readInts();
		
		int max = 0;
		int maxId = 0;
		for (int i = 0; i < nr; i++) {
			if(qs[i] >= max){
				max = qs[i];
				maxId = i;
			}
		}
		
		int apps = readInt();
		int[][] input = new int[apps][3];
		for (int i = 0; i < apps; i++) {
			input[i] = readInts();
		}
		
		int[] minCost = new int[nr];
		Arrays.fill(minCost, Integer.MAX_VALUE);
		
		for (int i = 0; i < apps; i++) {
			
			int emplyoee = input[i][1]-1;
			
			if(emplyoee == maxId){
				continue;
			}
			
			minCost[emplyoee] = Math.min(minCost[emplyoee],input[i][2]);
		}
		
		
		int sum = 0;
		
		for (int i = 0; i < minCost.length; i++) {
			if(i == maxId){
				continue;
			}
			
			if(minCost[i] == Integer.MAX_VALUE){
				System.out.println("-1");
				return;
			}
			sum += minCost[i];
			
		}
		System.out.println(sum);
		
	}

	static int id = -1;

	public int[] readInts() throws IOException {
		String[] split = readLine().split(" ");
		int[] ret = new int[split.length];
		for (int i = 0; i < split.length; i++) {
			ret[i] = Integer.parseInt(split[i]);
		}
		return ret;
	}

	public int readInt() throws IOException {
		return Integer.parseInt(readLine());
	}

	public String readLine() throws IOException {
		id++;
		if (test){
			return inData[id];
		} else {
			return in.readLine();
		}	
	}

	public static void main(String[] args) throws Throwable {
		new Main();
	}
}