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;
import java.util.StringTokenizer;

public class C {

	public static void main(String[] args) throws IOException {
		BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		StringTokenizer tokens = new StringTokenizer(stdin.readLine());
		
		int n = Integer.parseInt(tokens.nextToken());
		int m = Integer.parseInt(tokens.nextToken());
		int[] a = new int[n];
		int[] next = new int[n];
		tokens = new StringTokenizer(stdin.readLine());
		
		for (int i=0; i<n; i++) {
			a[i] = Integer.parseInt(tokens.nextToken());
			
		}
		
		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 found = false;
			tokens = new StringTokenizer(stdin.readLine());
			int l = Integer.parseInt(tokens.nextToken())-1;
			int r = Integer.parseInt(tokens.nextToken())-1;
			int x = Integer.parseInt(tokens.nextToken());
			for (int j=l; j<=r; j = next[j]) {
				if (a[j] != x) {
					out.println(j+1);
					found = true;
					break; 
				}
			}
			if (!found) out.println(-1);
			
		}
		out.flush();
		out.close();
		stdin.close();
	}

}