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.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.io.*;
import java.util.*;

public class EC7C
{

private static StringTokenizer st;
    
    public static void nextLine(BufferedReader br) throws IOException
    {
        st = new StringTokenizer(br.readLine());
    }
    
    public static int nextInt()
    {
        return Integer.parseInt(st.nextToken());
    }
    
    public static String next()
    {
        return st.nextToken();
    }
    
    public static long nextLong()
    {
        return Long.parseLong(st.nextToken());
    }

    public static double nextDouble()
    {
        return Double.parseDouble(st.nextToken());
    }
    
    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        nextLine(br);
        int n = nextInt();
        int m = nextInt();
        nextLine(br);
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
        {
            a[i] = nextInt();
        }
        int[] next = new int[n];
        Arrays.fill(next, -1);
        int ptr = 0;
        for (int i = 1; i < n; i++)
        {
            if (a[i] != a[ptr])
            {
                while (ptr < i)
                {
                    next[ptr] = i;
                    ptr++;
                }
            }
        }
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < m; i++)
        {
            nextLine(br);
            int l = nextInt() - 1;
            int r = nextInt() - 1;
            int x = nextInt();
            if (a[l] != x)
            {
                sb.append((l+1) + "\n");
            }
            else if (next[l] != -1 && next[l] <= r)
            {
                sb.append((next[l]+1) + "\n");
            }
            else
            {
                sb.append("-1\n");
            }
        }
        System.out.println(sb.toString());
    }

    
}