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.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class C {

    public static void main(String[] args) {
        try {
            solve(System.in, System.out);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static void solve(InputStream in, OutputStream out) throws Exception {
        InputReader inputReader = new InputReader(in);
        PrintWriter writer = new PrintWriter(new BufferedOutputStream(out));

        int n = inputReader.nextInt();
        int m = inputReader.nextInt();
        long[] a = new long[n];
        for (int i = 0; i < n; i++) {
            a[i] = inputReader.nextLong();
        }

        int[] d = new int[n];
        d[0] = -1;
        for (int i = 1; i < n; i++) {
            if (a[i] == a[i - 1]) {
                d[i] = d[i - 1];
            } else {
                d[i] = i - 1;
            }
        }

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

            if (a[r] == x) {
                if (d[r] >= l) {
                    writer.println(d[r] + 1);
                } else {
                    writer.println(-1);
                }
            } else {
                writer.println(r + 1);
            }
        }

        writer.close();
    }

    private 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());
        }
    }
}