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.math.BigInteger;
import java.util.*;

public class Main {

	long[] pred;
	double x1, x2, y1, y2, x3, y3, R;

	public void run() throws IOException {
		FastScanner in = new FastScanner();
		PrintWriter out = new PrintWriter(System.out);
		int n = in.nextInt();
		int m = in.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = in.nextInt();
		}
		int[] res = new int[n];
		res[0] = 1;
		for (int i = 1; i < res.length; i++) {
			if (a[i - 1] == a[i]){
				res[i] = res[i - 1] + 1;
			}else
				res[i] = 1;
		}
		for (int  i = 0; i < m ;i++){
			int l = in.nextInt() - 1;
			int r = in.nextInt() - 1;
			int x = in.nextInt();
			if (a[r] != x){
				out.println(r + 1);
			}else{
				if (res[r] >= r - l + 1)
					out.println(-1);
				else
					out.println(1 + r - res[r]);
			}
		}
		out.flush();
		out.close();
	}

	public static void main(String[] args) {
		try {
			new Main().run();
		} catch (IOException e) {
			e.printStackTrace();
			System.exit(42);
		}
	}

	class FastScanner {
		BufferedReader reader;
		StringTokenizer tokenizer;

		FastScanner() throws FileNotFoundException {
			reader = new BufferedReader(new InputStreamReader(System.in));
			tokenizer = null;
		}

		String next() throws IOException {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				tokenizer = new StringTokenizer(reader.readLine());
			}
			return tokenizer.nextToken();
		}

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

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

		double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		String readLine() throws IOException {
			return reader.readLine();
		}
	}
}