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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.TreeSet;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.util.Comparator;
import java.io.InputStream;

public class Main 
{
    public static void main(String[] args) 
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(in, out);
        out.close();
    }

    static class Task 
    {
        public void solve(InputReader sc, PrintWriter out) 
	    {
            int n = sc.nextInt();
            int m = sc.nextInt();
            int a[] = new int[n+1];
            int pp[] = new int[n+1];
            for(int i = 1; i < n+1; i++)
            {
                a[i] = sc.nextInt();
                if(a[i] != a[i-1])
                {
                    pp[i] = i-1;
                }
                else
                {
                    pp[i] = pp[i-1];
                }
            }
        for(int i = 0; i < m; i++)
        {
            int l = sc.nextInt();
            int r = sc.nextInt();
            int x = sc.nextInt();
            if(x != a[r])
            {
                out.println(r);
            }
            else if(pp[r] >= l)
            {
                out.println(pp[r]);
            }
            else
            {
                out.println(-1);
            }
        }
    }
}

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() 
	{
            while (tokenizer == null || !tokenizer.hasMoreTokens()) 
	    {
                try 
		{
                    tokenizer = new StringTokenizer(reader.readLine());
                } 
		catch (IOException e) 
		{
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() 
	{
            return Integer.parseInt(next());
        }

    }
}