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 c {
	public static void main(String[] args) throws IOException {
		in.init(System.in);
		PrintWriter out = new PrintWriter(System.out);

		int n = in.nextInt();
		int m = in.nextInt();
		int[] a = new int[n];
		for(int i = 0; i < n; i++)
			a[i] = in.nextInt();
		
		TreeSet<Integer> splits = new TreeSet<Integer>();
		for(int i = 0; i < n-1; i ++)
			if(a[i] != a[i+1])
				splits.add(i);
		
		for(int i = 0; i < m; i ++)
		{
			int l = in.nextInt() - 1;
			int r = in.nextInt() - 1;
			int x = in.nextInt();
			Integer split = splits.ceiling(l);
			
			if(split == null ||  split >= r)
				out.println(a[l]==x?-1:l+1);
			else
				out.println(a[split]==x?split+2:split+1);
		}
		out.close();
	}

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

		static void init(InputStream in) {
			reader = new BufferedReader(new InputStreamReader(in));
			tokenizer = new StringTokenizer("");
		}

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

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

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

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