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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	
	public static void main(String[] args) throws IOException {
		BufferedReader buffy = new BufferedReader(new InputStreamReader(
				System.in));
		StringTokenizer toki = new StringTokenizer (buffy.readLine());
		int arrayLength = Integer.parseInt(toki.nextToken());
		int numb_queries = Integer.parseInt(toki.nextToken());
		int[] array = new int[arrayLength + 1];
		int[] different_numb = new int[arrayLength + 1];
		toki = new StringTokenizer (buffy.readLine());
		different_numb [1] = -1;
		int pointer = arrayLength;//TODO
		for(int i= 1; i <= arrayLength; i++)
		{
			array[i] = Integer.parseInt(toki.nextToken());
		}
		//for(int i=arrayLength-1; i>0; i--)
		for(int i=2; i<=arrayLength; i++)
		{
			if(array[i-1] == array[i])
				 different_numb[i] =  different_numb[i-1];
			else{
				//pointer = i;
				different_numb[i] = i-1 ;
			}
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < numb_queries; i++) {
			toki = new StringTokenizer(buffy.readLine());
			int l = Integer.parseInt(toki.nextToken());
			int r = Integer.parseInt(toki.nextToken());
			int x = Integer.parseInt(toki.nextToken());;
			//int output = -1;
			if (x!= array[r]) {
				//output = r;
				sb.append(r);
			}
			else if(different_numb[r] >= l){
					//output = different_numb[r];
				sb.append(different_numb[r]);
			}
			else{
				sb.append("-1");
			}
			sb.append("\n");
		}
		System.out.println(sb);
	}
}