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.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.InputStreamReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author zodiacLeo
 */
public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC
    {
        public void solve(int testNumber, FastScanner in, PrintWriter out)
        {
            int n = in.nextInt();
            int q = in.nextInt();
            int a[] = new int[n];
            int dp[] = new int[n];
            for (int i = 0; i < n; i++)
            {
                a[i] = in.nextInt();
                if (i > 0)
                {
                    if (a[i] != a[i - 1])
                    {
                        dp[i] = i - 1;
                    } else
                    {
                        dp[i] = dp[i - 1];
                    }
                }
            }
            //System.out.println(Arrays.toString(dp));
            while (q-- > 0)
            {
                int left = in.nextInt() - 1;
                int right = in.nextInt() - 1;
                int value = in.nextInt();
                if (a[right] != value)
                {
                    out.println(right + 1);
                } else
                {
                    if (dp[right] < left)
                    {
                        out.println(-1);
                    } else
                    {
                        if (a[dp[right]] != value)
                        {
                            out.println(dp[right] + 1);
                        } else
                        {
                            out.println(-1);
                        }
                    }
                }
            }
        }

    }

    static class FastScanner
    {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream is)
        {
            br = new BufferedReader(new InputStreamReader(is));
        }

        public FastScanner(File f)
        {
            try
            {
                br = new BufferedReader(new FileReader(f));
            } catch (FileNotFoundException e)
            {
                e.printStackTrace();
            }
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                String s = null;
                try
                {
                    s = br.readLine();
                } catch (IOException e)
                {
                    e.printStackTrace();
                }
                if (s == null)
                    return null;
                st = new StringTokenizer(s);
            }
            return st.nextToken();
        }

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

    }
}