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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class CEdu7 {
	public static void main(String[] args) throws IOException {
		BufferedReader f = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		String[] split = f.readLine().split(" ");
		int n = Integer.parseInt(split[0]), m = Integer.parseInt(split[1]);
		int[] a = new int[n];
		split = f.readLine().split(" ");
		for(int i = 0; i < n; i++) a[i] = Integer.parseInt(split[i]);
		int[] next = new int[n];
		next[n-1] = n;
		for(int i = n-2; i >= 0; i--) {
			if(a[i] != a[i+1]) {
				next[i] = i+1;	
			} else {
				next[i] = next[i+1];
			}
		}
		for(int i = 0; i < m; i++) {
			boolean flag = false;
			split = f.readLine().split(" ");
			int l = Integer.parseInt(split[0])-1, r = Integer.parseInt(split[1])-1, x = Integer.parseInt(split[2]);
			for(int j = l; j <= r; j = next[j]) {
				if(a[j] != x) {
					out.println(j+1);
					flag = true;
					break;
				}
			}
			if(!flag) out.println(-1);
		}
		out.close();
	}
	
	static void printArray(int[] a) {
		for(int i = 0; i < a.length; i++) System.out.print(a[i] + " ");
		System.out.println();
	}
}