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:
/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		MyScanner sc = new MyScanner();
		int n = sc.nextInt();
		int p = sc.nextInt();
		int[] arr = new int[n];
		int[] dp = new int[n];
		for (int i = 0; i < n; ++i){
		    arr[i] = sc.nextInt();
		    dp[i] = 0;
		    if (i > 0){
		        if (arr[i] == arr[i-1]){
		            dp[i] = dp[i-1] + 1;
		        }
		    }
		}
		out = new PrintWriter(new BufferedOutputStream(System.out));
		for (int i = 0; i < p; ++i){
		    int l = sc.nextInt();
		    int r = sc.nextInt();
		    l--;
		    r--;
		    int ax = sc.nextInt();
		    
		    if (arr[r] != ax){
		        out.println(r+1);
		    }else{
		        int k = r - dp[r] - 1;
		        if (k >= l){
		            out.println(k+1);
		        }else{
		            out.println(-1);
		        }
		    }
		    
		}
		out.close();
	}
	
    //-----------PrintWriter for faster output---------------------------------
   public static PrintWriter out;
      
   //-----------MyScanner class for faster input----------
   public static class MyScanner {
      BufferedReader br;
      StringTokenizer st;
 
      public MyScanner() {
         br = new BufferedReader(new InputStreamReader(System.in));
      }
 
      String next() {
          while (st == null || !st.hasMoreElements()) {
              try {
                  st = new StringTokenizer(br.readLine());
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return st.nextToken();
      }
 
      int nextInt() {
          return Integer.parseInt(next());
      }
 
      long nextLong() {
          return Long.parseLong(next());
      }
 
      double nextDouble() {
          return Double.parseDouble(next());
      }
 
      String nextLine(){
          String str = "";
      try {
         str = br.readLine();
      } catch (IOException e) {
         e.printStackTrace();
      }
      return str;
      }
   }
}