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 static java.lang.Math.*; 

import java.io.*; 
import java.util.*; 
import java.math.*;

public class Main {
	BufferedReader in; 
	PrintWriter out;
	StringTokenizer st; 

	String next() {
		while (st==null || !st.hasMoreTokens()) {
			try {
				st = new StringTokenizer(in.readLine());
			} catch (Exception e) {}
		}
		return st.nextToken(); 
	}

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

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

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

	public void run() throws Exception {
		in = new BufferedReader(new InputStreamReader(System.in));
		out = new PrintWriter(System.out);
		int n = nextInt(), m = nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = nextInt();
		}
		int[] d = new int[n];
		d[0] = -1;		
		for (int i = 1; i < n; i++) {
			d[i] = a[i] != a[i - 1] ? i - 1 : d[i - 1];
		}
		for (int i = 0; i < m; i++) {
			int l = nextInt() - 1, r = nextInt() - 1, x = nextInt();
			if (a[r] != x) out.println(r + 1); else
			if (d[r] >= l) out.println(d[r] + 1); else
			out.println(-1);
		}                     
		out.close(); 
 	}
	
	public static void main(String[] args) throws Exception {
		new Main().run(); 
	}

}