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.*;
import java.util.*;
import java.math.*;
import static java.lang.Math.*;
import static java.lang.Integer.parseInt;
import static java.lang.Long.parseLong;
import static java.lang.Double.parseDouble;
import static java.lang.String.*;

public class Main {
    
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder out = new StringBuilder();
        StringTokenizer tk;
        
        tk = new StringTokenizer(in.readLine());
        int n = parseInt(tk.nextToken()),m = parseInt(tk.nextToken());
        int [] a = new int[n];
        tk = new StringTokenizer(in.readLine());
        for(int i=0; i<n; i++)
            a[i] = parseInt(tk.nextToken());
        
        int [] p = new int[n];
        p[0] = -1;
        for(int i=1; i<n; i++) {
            if(a[i]==a[i-1])
                p[i] = p[i-1];
            else p[i] = i-1;
        }
        
        while(m-- > 0) {
            tk = new StringTokenizer(in.readLine());
            int l = parseInt(tk.nextToken())-1,r = parseInt(tk.nextToken())-1,x = parseInt(tk.nextToken());
            
            if(a[r]!=x) out.append(r+1).append("\n");
            else if(p[r] < l) out.append("-1\n");
            else out.append(p[r]+1).append("\n");
        }
        
        System.out.print(out);
    }
}