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 CodeForces.EducationalRound7;

import javafx.util.Pair;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

/**
 * Created by ilya on 10.02.16.
 */

public class C622 {
    public static void main(String[] args) {
        sc sc = new sc();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(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 [] prev = new int[n];
        prev[0] = -1;
        outer:
        for (int i = 1; i < n; i++) {
            if (a[i]!=a[i-1]) {
                prev[i] = i-1;
            }
            else {
                prev[i] = prev[i-1];
            }
        }

        for (int i = 0; i < m; i++) {
            int l = sc.nextInt()-1;
            int r = sc.nextInt()-1;
            int x = sc.nextInt();
            if (a[r]!= x) out.println(r+1);
            else if (prev[r] >= l) out.println(prev[r]+1);
            else out.println(-1);
        }
        out.close();
    }

    static int noti(Pair<Integer,Integer>[] a, int i, int l, int r){
        if (a[l].getValue() != i) return a[l].getKey()+1;
        else if (a[r].getValue() != i) return a[r].getKey()+1;
        else return -1;
    }

    public static class sc {
        BufferedReader br;
        StringTokenizer st;

        public sc() {
            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();
        }

        Integer 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;
        }
    }

}