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:
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author sarthak
 */

import java.util.*;
import java.math.*;
import java.io.*;



public class eduRnd7_C {
    static class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream is) {
            br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }
    }
    static class P implements Comparable{

        private int x, y;

        public P(int x, int y) {
            this.x = x;
            this.y = y;
        }

        public int hashCode() {
            return (x * 31) ^ y;
        }

        public boolean equals(Object o) {
            if (o instanceof P) {
                P other = (P) o;
                return (x == other.x && y == other.y);
            }
            return false;
        }
        public int compareTo(Object obj) {
		P l = (P) obj;
		if (this.x == l.x){
			if (this.y == l.y) return 0;
			return (this.y < l.y)? -1: 1;
		}
		return (this.x < l.x)? -1: 1;
	}
    }
    public static void main(String[] args){
    FastScanner s = new FastScanner(System.in);
    StringBuilder op=new StringBuilder();
    int n=s.nextInt();
    int m=s.nextInt();
    int[] a=new int[n+1];
    for(int i=1;i<=n;i++){
        a[i]=s.nextInt();
    }
    int[] Pp=new int[n+1];
    Pp[1]=-1;
    for(int i=2;i<=n;i++)
        if(a[i-1]!=a[i])
            Pp[i]=i-1;
        else Pp[i]=Pp[i-1];
    
    for(int i=1;i<=m;i++){
        int l=s.nextInt();
        int r=s.nextInt();
        int e=s.nextInt();
        if(a[r]!=e)op.append(r+"\n");
        else if(Pp[r]<l)op.append(-1+"\n");
        else op.append(Pp[r]+"\n");
        
        
        
    }
    System.out.println(op);;
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    }


}