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.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;
/**
 *
 * @author Sourav Kumar Paul
 */
public class SolveCC {
    public static void main(String[] args) throws IOException{
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        StringTokenizer st = new StringTokenizer(reader.readLine());
        int n = Integer.parseInt(st.nextToken());
        int m = Integer.parseInt(st.nextToken());
        int arr[] = new int[n];
        int prefix[] = new int[n];
        int suffix[] = new int[n];
        st = new StringTokenizer(reader.readLine());
        for(int i=0; i<n; i++)
        {
            arr[i] = Integer.parseInt(st.nextToken());
            
            if(i==0)
                prefix[i] = -1;
            else
            {
                if(arr[i] == arr[i-1])
                    prefix[i] = prefix[i-1];
                else
                    prefix[i] = i-1;
            }
        }
        for(int i= n-1; i>=0; i--)
        {
            if(i == n-1)
                suffix[i] = n+1;
            else
            {
                if(arr[i] == arr[i+1])
                suffix[i] = suffix[i+1];
                else
                    suffix[i] = i+1;
            }
        }
       // System.out.println(Arrays.toString(prefix));
       // System.out.println(Arrays.toString(suffix));
        for(int i=0; i<m; i++)
        {
            st = new StringTokenizer(reader.readLine());
            int l = Integer.parseInt(st.nextToken()) - 1;
            int r = Integer.parseInt(st.nextToken()) - 1;
            int x = Integer.parseInt(st.nextToken());
            boolean flag = false;
            if(arr[r] != x)
            {
                out.println(r+1);
                flag = true;
            }
            else
            {
                int index = prefix[r];
                if(index >= l)
                {
                   out.println(index+1);
                    flag = true;
                }
                
            }
            
            if(arr[l] != x && !flag)
            {
                out.println(l+1);
                flag = true;
            }
            else if(!flag)
            {
                int index = suffix[l];
                if(index <= r)
                {
                   out.println(index+1);
                    flag = true;
                }
            }
            if(!flag)
                out.println("-1");
        }
        out.flush();
        out.close();
            
    }
}