Problem: You are given array a with n integers and m queries. The i-th query is given with three integers li, ri, xi.

For the i-th query find any position pi (li ≤ pi ≤ ri) so that api ≠ xi.

Input

The first line contains two integers n, m (1 ≤ n, m ≤ 2·105) — the number of elements in a and the number of queries.

The second line contains n integers ai (1 ≤ ai ≤ 106) — the elements of the array a.

Each of the next m lines contains three integers li, ri, xi (1 ≤ li ≤ ri ≤ n, 1 ≤ xi ≤ 106) — the parameters of the i-th query.

Output

Print m lines. On the i-th line print integer pi — the position of any number not equal to xi in segment [li, ri] or the value  - 1 if there is no such number.

Examples

Input

6 4
1 2 1 1 3 5
1 4 1
2 6 2
3 4 1
3 4 2


Output

2
6
-1
4

Solution (in JAVA):

Solution:
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * @author asif.hossain
 * @since 2/14/16
 */
public class P622C {
    public static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    public static BufferedOutputStream writer = new BufferedOutputStream(System.out);
     
    public static void main(String[] args) throws IOException {
        String line = reader.readLine();
        int n = Integer.parseInt(line.split("\\s")[0]);
        int m = Integer.parseInt(line.split("\\s")[1]);

        
        String[] numbers = reader.readLine().split("\\s");
        int[] mappings = new int[n + 1];
        
        mappings[1] = 1;
        mappings[0] = -1;
        int leftPos = 1;
        for (int i = 2; i <= n; i++) {
            if (!numbers[i-1].equals(numbers[i-2])) {
                leftPos = i;
            }
            mappings[i] = leftPos;

        }
//        ArrayUtils.printArray(numbers);
//        ArrayUtils.printArray(mappings);
        for (int i = 1; i <= m; i++) {
            line = reader.readLine();
            int l = Integer.parseInt(line.split("\\s")[0]);
            int r = Integer.parseInt(line.split("\\s")[1]);
            String x = line.split("\\s")[2];

            if (!numbers[r-1].equals(x)) {
                writer.write((r + "\n").getBytes());
            }
            else if (l < mappings[r]) {
                writer.write(((mappings[r] - 1) + "\n").getBytes());
            } 
            else {
                writer.write((-1 + "\n").getBytes());
                
            }
        }
        writer.flush();

    }
}