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 Send {
    private static InputReader in;

    public static void main(String[] args) {
        in = new InputReader(System.in);
        PrintWriter out = new PrintWriter(System.out, true);

        int n = in.nextInt();
        int m = in.nextInt();
        int[] a = new int[n];
        int[] counts = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = in.nextInt();
            counts[i] = 1;
            if (i > 1 && a[i] == a[i - 1]) {
                counts[i] = counts[i - 1] + 1;
            }
        }

        for (int i = 0; i < m; i++) {
            int l = in.nextInt() - 1;
            int r = in.nextInt() - 1;
            int x = in.nextInt();

            int d = r - counts[r];

            if (a[r] != x) {
                out.println(r + 1);
            } else if (d >= l) {
                if (d == 0 && a[0] == x) {
                    out.println(-1);
                } else {
                    out.println(r - counts[r] + 1);
                }
            } else {
                out.println(-1);
            }
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

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