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.util.*;

import java.io.*;
public class C622 {
public static void main(String[] args) throws IOException
{
	FS input = new FS(System.in);
	int n = input.nextInt(), m = input.nextInt();
	int[] as= new int[n];
	for(int i = 0; i<n; i++) as[i] = input.nextInt();
	int[] next = new int[n];
	next[n-1] = n;
	for(int i = n-2; i>=0; i--)
	{
		next[i] = (as[i] == as[i+1]) ? next[i+1] : i+1;
	}
	PrintWriter out = new PrintWriter(System.out);
	for(int i = 0; i<m; i++)
	{
		int a = input.nextInt()-1, b = input.nextInt()-1, x = input.nextInt();
		if(as[a] != x) out.println(a+1);
		else
		{
			int min = next[a];
			if(min <= b) out.println(min+1);
			else out.println(-1);
		}
	}
	out.close();
}
static class FS
{
	BufferedReader br;
	StringTokenizer st;
	public FS(InputStream in)
	{
		br = new BufferedReader(new InputStreamReader(in));
	}
	String next() throws IOException
	{
		while(st == null || !st.hasMoreTokens()) st = new StringTokenizer(br.readLine());
		return st.nextToken();
	}
	int nextInt() throws IOException
	{
		return Integer.parseInt(next());
	}
}
}