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.PrintWriter;
import java.math.BigDecimal;
import java.util.*;

import static java.lang.Math.max;

public class C {


    public static void main(String[] args) {

        MyScanner in = new MyScanner();
        int n = in.nextInt();
        int m = in.nextInt();
        int[] a = new int[n];

        for(int i=0;i<n;++i){
            a[i] = in.nextInt();
        }

        int[] prevDiff = new int[n];
        prevDiff[0] = -1;
        for(int i=1;i<n;++i){
            if(a[i]==a[i-1]){
                prevDiff[i] = prevDiff[i-1];
            }else{
                prevDiff[i] = i-1;
            }
        }

        out = new PrintWriter(System.out);

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

    }
    //--------------------------------------------------------


}