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.*;

public class Solution
{
       public static void main(String []args)
       {
              Scanner sc = new Scanner(System.in);
              int n = sc.nextInt();
              int m = sc.nextInt();
              
              int arr[] = new int[n];
              for(int i = 0 ; i < n ; i++)
              {
                     arr[i] = sc.nextInt();
              }
              
              int equal[] = new int[n];
              int i = 0;
              while(i < n)
              {
                     int j = i;
                     while(j+1 < n && arr[j+1] == arr[j])
                     {
                            j++;
                     }
                     
                     for(int k = i ; k <= j ; k++)
                     {
                            equal[k] = j;
                     }
                     i = j+1;
              }
              StringBuffer str = new StringBuffer("");
              while(m-- > 0)
              {
                     int l = sc.nextInt()-1;
                     int r = sc.nextInt()-1;
                     int x = sc.nextInt();
                     if(arr[l] != x)
                     str.append((l+1)+"");
                     
                     else
                     {
                            if(equal[l] >= r)
                            str.append("-1");
                            
                            else
                            str.append((equal[l]+2)+"");
                     }
                     str.append(System.lineSeparator());
              }
              System.out.println(str);
       }
}