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

public class Main {
    static class Pair{
        int x;
        int y;
        Pair(int x,int y){
            this.x=x;
            this.y=y;
        }
    }
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;
        FastReader() { 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;
        }
    }

    private static boolean isInside(int i, int j, int n, int m){
        if(i>=0 && i<n && j>=0 && j<m){
            return true;
        }
        return false;
    }


    public static void main(String[] args) throws IOException {
        FastReader ip = new FastReader();
        OutputStream output = System.out;
        PrintWriter out = new PrintWriter(output);
        int n=ip.nextInt();
        int m=ip.nextInt();
        int arr[]=new int[n];
        for(int i=0;i<n;i++){
            arr[i]=ip.nextInt();
        }
        int pos[]=new int[n];
        pos[0]=-1;
        for(int i=1;i<n;i++){
            if(arr[i]==arr[i-1]){
                pos[i]=pos[i-1];
            }else{
                pos[i]=i-1;
            }
        }
        while(m-->0){
            int l=ip.nextInt();
            int r=ip.nextInt();
            int x=ip.nextInt();
            l--;
            r--;
            if(arr[r]!=x){
                out.println(r+1);
            }else{
                if(pos[r]>=l) {
                    out.println(pos[r] + 1);
                }else{
                    out.println(-1);
                }
            }
        }
        out.close();
    }
}