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 C {
    public static void main(String[] args) {
        MyScanner in = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = in.nextInt();
        int m = in.nextInt();

        int[] a = new int[n];
        int[] next = new int[n];
        next[n-1] = -2;
        for (int i = 0; i < n; i++) {
            a[i] = in.nextInt();
        }

        for (int i = n-2; i >= 0; i--) {
            if (a[i] != a[i+1]) next[i] = i+1;
            else next[i] = next[i+1];
        }


        int[] ans = new int[m];
        for (int i = 0; i < m; i++) {
            int l = in.nextInt();
            int r = in.nextInt();
            int x = in.nextInt();
            ans[i] = query(a, next, l-1, r-1, x);
        }

        for (int i : ans) {
            out.println(i+1);
        }
        out.close();

    }

    private static int query (int[] a, int[] next, int l, int r, int x) {
        if (a[l] != x) return l;
        if (next[l] > r) return -2;
        return next[l];
    }

    public static PrintWriter out;

    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());
        }
    }
}