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.List;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map.Entry;
import java.util.Queue;
import java.util.Scanner;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.Vector;
 
 
public class Main {
	
	public static void main(String[] args) throws IOException{
		  	FastScanner sc = new FastScanner();
			PrintWriter out = new PrintWriter(System.out);
			int n = sc.nextInt();
			int m =sc.nextInt();
			int a[]=new int[n];
			for(int i=0;i<n;i++)a[i]=sc.nextInt();
			int ne[]=new int[n];
			Arrays.fill(ne, -1);
			int i=0;int j=0;
			while(i<n){
				while(i<n && j<n &&a[j]==a[i]){
					j++;
				}
				ne[i]=j;
				i=j;
				
			}
			
			for( i=0;i<n;i++)
				if(ne[i]==-1)
					ne[i]=ne[i-1];
				;
			for(i=0;i<m;i++){
				int l =sc.nextInt();
				int r =sc.nextInt();
			int x =sc.nextInt();
			if(a[l-1]!=x){
				out.println(l);
				continue;
			}
			int pos =ne[l-1];
			if(pos<=r-1){
				out.println(pos+1);
				continue;
			}
			out.println(-1);
			
			}
			out.close();
			}
			
			

		

	
	

	
	
	

			
						
			

	
	

		
		
		



	
	
	
	
	
	static void generate(int[] p, int L, int R) {
		  if (L == R) {
			  
		  
		  }else { // numbers at positions [0, L-1] are set, try to set L-th position
		    for (int i = L; i <= R; i++) {
		    	int tmp = p[L]; p[L] = p[i]; p[i] = tmp;
		      generate(p, L+1, R);
		      tmp = p[L]; p[L] = p[i]; p[i] = tmp;

		    }
		  }
		}
	
}
		 


	
	
	
	











	
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
class FastScanner {
 
 
 
 
    BufferedReader br;
    StringTokenizer st;
 
    public FastScanner() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public FastScanner(String s) {
        try {
            br = new BufferedReader(new FileReader(s));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
 
    String nextToken() {
        while (st == null || !st.hasMoreElements()) {
            try {
 
                st = new StringTokenizer(br.readLine());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    int nextInt() {
        return Integer.parseInt(nextToken());
    }
 
    long nextLong() {
        return Long.parseLong(nextToken());
    }
 
    double nextDouble() {
        return Double.parseDouble(nextToken());
    }
 
 
}