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:
/*
 * CSE 2013, NIT SILCHAR
 */
//package EducationalRound7;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import static java.lang.System.out;
import java.util.StringTokenizer;

/**
 *
 * @author Nikhil Pathania
 */
public class C {
    public static void main(String args[]) throws IOException
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int n=Integer.parseInt(str[0]);
        int m=Integer.parseInt(str[1]);
        int arr[]=new int[n];
        StringTokenizer st=new StringTokenizer(br.readLine());
        for(int i=0;i<n;i++)
        {
        arr[i]=Integer.parseInt(st.nextToken());
        }
        
        int pref[]=new int[n];
        pref[0]=-1;
       // out.print(pref[0]+" ");
        for(int i=1;i<n;i++)
        {
            if(arr[i]==arr[i-1])
            {
                pref[i]=pref[i-1];
            }
            else
            {
                pref[i]=i-1;
            }
         //   out.print(pref[i]+" ");
        }
        int index;
        for(int i=0;i<m;i++)
        {
        st=new StringTokenizer(br.readLine());
        int l=Integer.parseInt(st.nextToken());
        int r=Integer.parseInt(st.nextToken());
        int x=Integer.parseInt(st.nextToken());
        l=l-1;
        r=r-1;
        if(arr[r]!=x)
        {
           pw.println(r+1); 
        }
        else
        {
           if(pref[r]>=l)
           {
               pw.println(pref[r]+1);
           }
           else
           {
               pw.println(-1);
           }
        }
        pw.flush();
        }
        
    }
}