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.*;

public class Codeforces {

    public  void solve() {
        FastScanner fs = new FastScanner();
        PrintWriter out = new PrintWriter(System.out);
        int n = fs.nextInt(), m = fs.nextInt();
        int[]ar = new int[n];
        for(int i=0;i<n;i++)
            ar[i] = fs.nextInt();
        int[]z = new int[n+1];
        z[0] = -1;
        for(int i=1;i<n;i++){
            if(ar[i] == ar[i-1])z[i]=z[i-1];
            else z[i] = i-1;
        }
        for(int i=0;i<m;i++){
            int l = fs.nextInt()-1, r = fs.nextInt()-1, x = fs.nextInt();
            if( ar[r] != x ){
                out.println(r+1);
            }else if(l <= z[r]){
                out.println(z[r]+1);
            }else{
                out.println("-1");
            }
        }
        out.flush();

    }

    public static void main(String[]args){
        try{
            new Codeforces().solve();
        }catch (Exception e){
            e.printStackTrace();
        }

    }
    static class FastScanner {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st=new StringTokenizer("");
        String next() {
            while (!st.hasMoreTokens())
                try {
                    st=new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() {
            return Long.parseLong(next());
        }
    }
}